Silica
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Worker exposure to silica in construction projects is a significant concern because silica is one of the main constituents of many construction materials. Prolonged or repeated exposure to uncombined crystalline silica at airborne concentrations above established occupational exposure limits can cause damage to lungs (silicosis) and may cause cancer.
Construction materials containing silica include:
- abrasives used for blasting (sandblasting)
- concrete, concrete block, cement, mortar
- brick, refractory brick
- granite, sandstone, quartzite, slate
- gunite (a mixture of water, cement, and sand)
- mineral deposits
- stone and rock
- sand, soil and fill dirt
- asphalt containing rock or stone
Many construction activities and processes release airborne silica-containing dust. Abrasive blasting generates the most dust. Abrasive blasting is the cleaning, smoothing, roughening or removing of part of the surface of any article by using a jet of sand, metal shot, grit or other material. Exposure to silica from abrasive blasting can occur if the abrasive contains silica (sandblasting). Exposure to silica from abrasive blasting can also occur if the material being blasted contains silica. Other processes that generate airborne dust include:
- rock excavating and processing activities such as:
- cutting, splitting, chipping, hammering, drilling, crushing, sieving, loading, hauling, and dumping of gravel or rock that contains more than 5% crystalline silica
- concrete and masonry activities such as:
- sawing, hammering, drilling, grinding, and chipping and demolition of concrete and masonry structures
- dry sweeping or pressurized air blowing of concrete, rock, or sand dust
- road construction
- sweeping, cleaning, and dismantling equipment
- tunneling, excavation, and earth moving high silica-containing soils.
An employer or contractor shall:
- Warn workers about the health hazards associated with inhaling dust containing silica if any part of their work will involve a silica process or if the workers are likely to be exposed to silica dust.
- Take all practicable steps to prevent inhalation of silica dust or dissemination of silica dust into the air of the workplace during cleaning or maintenance of:
- Ensure all worksites and work-related areas are regularly cleaned where dust from a silica process may affect the health or safety of workers.
- Ensure that silica dust from a silica process other than abrasive blasting, is prevented as far as practicable, from entering the air where workers may be present by providing:
- Ensure that any enclosure, apparatus or exhaust-ventilation equipment provided is:
- Maintained;
- Inspected daily when in use;
- Certified as safe and effective by a competent person at least annually.
- Ensure that no air discharged from a local exhaust ventilation system recirculates in the work place unless the air passes through an effective dust removal system. The system must be equipped with a warning device that alerts workers when it malfunctions.
- Isolate workers, where practicable, from any air containing dust released from a silica process that cannot practicably be prevented.
- Provide and ensure workers wear respiratory protective devices and other personal protective equipment meeting the requirements of PART VII where:
- Provide and maintain approved blasting hoods for workers doing abrasive blasting. The air supply must be delivered at a volume of at least 170 litres per minute (l/min) and at a pressure less than 140 kilopascals (kPa).
- Provide and maintain respiratory protective devices meeting requirements of Part VII for workers possibly exposed to dust from abrasive blasting.
- Ensure that every blasting enclosure is:
- constructed, operated and maintained to prevent the escape of dust;
- provided with an efficient, dust-extraction system, operating continuously whenever blasting enclosure is in use, whether or not abrasive blasting is taking place;
- provided with efficient equipment for separating abrasive from dust, where practicable.
- Ensure that an abrasive is not reintroduced into a blasting apparatus until the abrasive has been separated from the dust.
- Ensure that:
- Ensure that a competent person must record the results of their examinations and tests of a blasting enclosure, connected equipment, and associated ventilating system.
- Ensure that:
- No abrasive blasting of articles that may produce dust containing uncombined silica is done in a blasting enclosure, where practicable;
- No sand or other substance containing more than 1% by weight of uncombined silica is used for abrasive blasting in a blasting enclosure, where practicable;
- Only abrasive blasting and work immediately incidental to abrasive blasting, and, cleaning and maintenance of the blasting enclosure, connected equipment, and the associated ventilating system are performed in a blasting enclosure.
- Ensure that no sandblasting is done to any article outside a blasting enclosure if sandblasting can be done in a blasting enclosure, where reasonably practicable.
- Ensure that no sandblasting is done inside any structure or confined space without written permission of the director and complying with any conditions specified by the director.
- Ensure that no silica flour is used;
- Arrange, no more than once a year, a medical examination for a worker regularly working in a silica process. The medical examination must be requested by the worker and conducted during the worker’s normal working hours.
- Reimburse the worker for any part of the medical examination costs that the worker cannot recover.
- Credit a worker’s attendance at a medical examination as time at work when the worker cannot attend a medical examination during their normal working hours and ensure that the worker does not lose any pay or other benefits.
- Ensure that a worker’s medical examination includes:
An owner shall:
- Take all practicable steps to prevent inhalation of silica dust or dissemination of silica dust into the air of the workplace during cleaning or maintenance of:
- If mining is carried out underground in strata containing uncombined silica in a crystalline form, an employer or contractor shall:
- minimize the release of dust into the general mine air during construction, use and maintenance of every ore pass, if reasonably practicable;
- provide an effective means to spray water within a suitable distance of the working face of every drift or raise to suppress any dust;
- spray water for a minimum of 15 minutes after any blasting operation is complete;
- provide every drill with a water jet, spray or other suitable attachment to prevent dust from escaping and ensure that the attachment is used at all times during a drilling operation.
Contamination Limits
| CAS Number | Substance | 8 hour average contamination limit mg/m³* or ppm* | 15 minute average contamination limit mg/m³* or ppm* | Notation |
| Silica Amorphous: | ||||
| 69012-46-2 | Silica, fume (respirable fraction) | 2 mg/m3 | ||
| 60676-86-0 | Silica, fused (respirable fraction) | 0.1 mg/m3 | ||
| Silica - Crystalline#: | ||||
| 14464-46-1 | Cristobalite (respirable fraction) | |||
| 14808-60-7 | Quartz (respirable fraction) | |||
| 1317-95-9 | Tripoli, as quartz (respirable fraction) |
**C - ceiling limit.
# - Trydimite removed.
Respirable fraction:
For the application of this limit, the respirable fraction is that fraction of the aerosol that passes a size selector with the following characteristics:
Table B
| Particle Aerodynamic Diameter (µm) | Respirable Particle Mass (RPM) (%) |
0 | 100 |
1 | 97 |
2 | 91 |
3 | 74 |
4 | 50 |
5 | 30 |
6 | 17 |
7 | 9 |
8 | 5 |
10 | 1 |
Occupational Health and Safety Regulations, 1996
S.S., c. O-1.1, Reg 1
Part I Preliminary Matters
Section 2 Interpretation
2. (1) In these regulations and in all other regulations made pursuant to the Act:
(a) "Act" means The Occupational Health and Safety Act, 1993 ;
(b) "air-purifying respirator" means a respirator that removes airborne contaminants from the air inhaled by a worker;
(c) "approved" means:
(i) approved by an agency acceptable to the director for use under the conditions prescribed by the agency; or
(ii) approved conditionally or otherwise by a certificate of the director;
(d) "atmosphere-supplying respirator" means a respirator that delivers clean breathing air to a worker from a compressor or a cylinder, an SCBA, whether closed or open circuit, or a combination of SCBA and supplied air;
(e) "borehole" means a mechanically drilled hole in the ground;
(f) "building shaft" means a continuous vertical space substantially enclosed on all sides that extends for two or more floors, and includes an elevator shaft, a ventilation shaft, a stairwell and a service shaft;
(g) "class A qualification" means a certificate or certificates that:
(i) are issued by an agency, as defined in section 50, with respect to the successful completion of a first aid training course and a cardiopulmonary resuscitation training course that meet the minimum requirements for course duration and content set out in Table 1 of the Appendix; and
(ii) qualify the holder to perform the services set out in Table 2 of the Appendix;
(h) "class B qualification" means a certificate or certificates that:
(i) are issued by an agency, as defined in section 50, with respect to the successful completion of a first aid training course and a cardiopulmonary resuscitation training course that meet the minimum requirements for course duration and content set out in Table 3 of the Appendix; and
(ii) qualify the holder to perform the services set out in Table 4 of the Appendix;
(i) "Class C fire" means a fire involving energized electrical equipment;
(j) "co-chairpersons" means, with respect to a committee, the employer or contractor co-chairperson appointed pursuant to clause 43(1)(b) and the worker co-chairperson elected pursuant to clause 43(1)(a);
(k) "committee" means an occupational health committee;
(l) "competent" means possessing knowledge, experience and training to perform a specific duty;
(m) "competent worker", with respect to a particular task or duty, includes a worker who is being trained to perform that task or carry out that duty and who is under close and competent supervision during that training;
(n) "connecting linkage" means a lanyard, safety hook, cable or connector inserted between a personal fall arrest system and the D-ring on a worker's full-body harness;
(o) "construction" means the erection, alteration, renovation, repair, dismantling, demolition, structural maintenance and painting of a structure, and includes:
(i) land clearing, earth moving, grading, excavating, trenching, digging, boring, drilling, blasting and concreting; and
(ii) the installation of any plant;
(p) "controlled product" means a controlled product within the meaning of the Hazardous Products Act (Canada);
(q) "dBA" means the sound pressure level in decibels measured on the A scale of a sound level meter;
(r) "dBA Lex" means the level of a worker's total exposure to noise, in dBA, averaged over an entire workday and adjusted to an equivalent eight-hour exposure;
(s) "designated signaller" means a worker designated pursuant to clause 132(1)(a) to give signals;
(t) "emergency medical technician" means a person who is licensed as an emergency medical technician, emergency medical technician-advanced or emergency medical technician-paramedic pursuant to The Ambulance Act;
(u) "escape respirator" means an atmosphere-supplying respirator or an air-purifying respirator that is designed to be used by a worker for escape purposes only;
(v) "excavated shaft" means a dug-out passage into the ground, the longest dimension of which exceeds 1.5 metres and of which the acute angle between the axis of the longest dimension and the vertical is less than 45;
(w) "excavation" means any dug-out area of ground other than a trench, tunnel or excavated shaft;
(x) "fall-arresting device" Repealed. [Sask. Reg. 67/2007, s. 3]
(y) "first aid" means immediate assistance given in case of injury until medical aid has been obtained;
(z) "first aid attendant" means the holder of a valid:
(i) class A qualification;
(ii) class B qualification;
(iii) emergency medical technician's licence; or
(iv) licence, certificate or other qualification that, in the opinion of the director, is equivalent to or superior to a qualification set out in subclauses (i) to (iii);
(aa) "first aid register" means the register required by section 57;
(bb) "first aid station" means a work-related area containing the supplies and equipment required by subsection 56(1);
(bb.1) "forklift" means a self-propelled machine that has a power-operated upright, angled or telescoping lifting device that can raise and lower a load for the purpose of transporting or stacking;
(cc) "full-body harness" means a safety device that is capable of suspending a worker without causing the worker to bend at the waist, and consists of straps that pass over the worker's shoulders and around the worker's legs, an upper dorsal suspension assembly and all integral hardware;
(dd) "hand tool" means hand-held equipment that is powered by the energy of a worker;
(ee) "harmful" means known to cause harm or injury;
(ff) "hazardous" means likely to cause harm or injury in certain circumstances;
(gg) "HEPA filter" means a high-efficiency particulate aerosol filter that is at least 99.97% efficient in collecting a 0.3 micrometre aerosol;
(hh) "hoist" means a machine that consists of a raising and lowering mechanism;
(ii) "immediately dangerous to life or health" means a condition in which a hazardous atmosphere exists to such an extent that a worker who is not using an approved respiratory protective device will suffer escape-impairing or irreversible health effects if the worker does not leave the hazardous atmosphere within 30 minutes;
(jj) "instruct" means to give information and direction to a worker with respect to particular subject-matter;
(kk) "lifeline" means a length of rope or strap that is attached to a safe point of anchorage at one end or, in the case of a horizontal lifeline, at both ends to provide support and a guide for a personal fall arrest system or personnel lowering device;
(ll) "locked out" means to have isolated the energy source or sources from equipment, to have dissipated any residual energy in a system and to have secured the isolation by a device that is operated by a key or other process;
(mm) "machine" means any combination of mechanical parts that transmits from one part to another or otherwise modifies force, motion or energy;
(nn) "maintained" means kept in a condition of efficient and safe functioning by a system of regular examination, testing and servicing or repair;
(oo) "The Mines Regulations" means The Mines Regulations, 2003 ;
(pp) "officer" means an occupational health officer;
(qq) "operator" means a person who operates any equipment;
(qq.1) "percutaneous" means a route of entry that is through the skin or mucous membrane, and includes subcutaneous, intramuscular and intravascular routes of entry.
(qq.2) "personal fall arrest system" means personal protective equipment that provides a means of safely arresting the fall of a worker and that, subsequent to the arrest of the fall, does not by itself permit the further release or lowering of the worker;
(rr) "personal protective equipment" means any clothing, device or other article that is intended to be worn or used by a worker to prevent injury or to facilitate rescue;
(ss) "personnel lowering device" means a device that provides a means of lowering a worker from a height at a controlled rate of descent;
(tt) "power tool" means a hand-held machine that is powered by energy other than the energy of a worker;
(uu) "powered mobile equipment" means a self-propelled machine or a combination of machines, including a prime mover, that is designed to manipulate or move materials or to provide a work platform for workers;
(vv) "professional engineer" means an engineer who is registered pursuant to The Engineering Profession Act;
(ww) "public highway" means a public highway as defined in The Highways and Transportation Act, 1997 ;
(xx) "qualified" means possessing a recognized degree, a recognized certificate or a recognized professional standing and demonstrating, by knowledge, training and experience, the ability to deal with problems related to the subject-matter, the work or the project;
(yy) "representative" means an occupational health and safety representative;
(zz) "respiratory protective device" means a device that is designed to protect a wearer from inhaling a hazardous atmosphere, and includes an atmosphere-supplying respirator, an air-purifying respirator and an escape respirator;
(aaa) "safeguard" means a guard, shield, wire mesh, guardrail, gate, barrier, safety net, handrail or other similar equipment that is designed to protect the safety of workers, but does not include personal protective equipment;
(bbb) "safety belt" Repealed. [Sask. Reg. 67/2007, s. 3]
(ccc) "SCBA" means self-contained breathing apparatus;
(ddd) "supervisor" means a person who is authorized by an employer to oversee or direct the work of workers;
(eee) "train" means to give information and explanation to a worker with respect to a particular subject-matter and require a practical demonstration that the worker has acquired knowledge or skill related to the subject-matter;
(fff) "travelway" means any place where workers or vehicles regularly travel or pass, and includes a ramp, runway, catwalk, bridge, conveyor, gantry or passage;
(ggg) "trench" means an elongated dug-out area of land whose depth exceeds its width at the bottom;
(hhh) "tunnel" means an underground passage that has an incline of not more than 45 from the horizontal;
(iii) "vehicle" means a machine in, on or by which a person or thing may be transported, and includes powered mobile equipment;
(jjj) "work" and "at work" means:
(i) the time during which a worker is in the course of the worker's employment; or
(ii) the time that a self-employed person devotes to work as a self-employed person;
(kkk) "work-related area" means all places that are ancillary to a place of employment, and includes lunchrooms, restrooms, first aid rooms, lecture rooms, parking lots under the control of the employer or contractor, offices and work camp living accommodations, but does not include a permanent living accommodation.
(2) For the purposes of the Act and in these regulations and all other regulations made pursuant to the Act, "injury" includes any disease and any impairment of the physical or mental condition of a person.
(3) Any word or expression used but not defined in these regulations or the Act has the meaning commonly given to it at places of employment in the industry concerned.
(4) Unless otherwise expressly stated:
(a) lumber sizes specified in these regulations are lumber sizes after dressing; and
(b) "lumber" means lumber that is free of visible defects.
[Sask. Reg. 6/97, s. 3; 35/2003, s. 3; 112/2005, s. 3; 67/2007, s. 3]
3. Repealed. [Sask. Reg. 35/2003, s. 4]
Part XXIV Silica Processes and Abrasive Blasting
Section 348 Warning of workers
348. An employer shall warn all workers who, in the course of employment, are likely to be engaged in a silica process or are likely to be exposed to silica dust of the dangers to health from the inhalation of dust containing silica.
Section 349 Cleaning of blasting equipment, etc.
349. An employer, contractor or owner shall take all practicable steps to prevent the inhalation of silica dust or the dissemination of silica dust into the air of the place of employment during the cleaning or maintenance of any blasting equipment, blasting enclosure, ventilating system or separating equipment.
Section 350 Cleaning of worksites
350. An employer or contractor shall ensure that all worksites and work-related areas where dust from a silica process may affect the health or safety of a worker are regularly cleaned using a vacuum that has a HEPA filter on the exhaust or, where a vacuum is not practicable, by using wet methods.
Section 351 Silica processes other than abrasive blasting
351. (1) Where a silica process other than abrasive blasting is carried on, an employer or contractor shall ensure that the entry of dust into the air where workers may be present is prevented, to the extent that is practicable, by the provision of:
(a) total or partial enclosure of the process;
(b) efficient local exhaust ventilation;
(c) jets or sprays of a suitable wetting agent; or
(d) any other method that provides equivalent protection to the workers.
(2) An employer or contractor shall ensure that any enclosure, apparatus or exhaust-ventilation equipment provided pursuant to subsection (1) is:
(a) maintained in accordance with subsections 67(2) and (3);
(b) inspected daily when in use; and
(c) certified as safe and effective by a competent person at least once each year.
(3) An employer or contractor shall ensure that no air discharged from a ventilation system provided pursuant to subsection (1) is recirculated in the place of employment unless the air is passed through an effective dust removal system equipped with a device that will provide a warning to workers when the system is not working effectively.
[Sask. Reg. 6/97, s. 12]
Section 352 Isolation from air containing dust
352. Where it is not practicable to prevent the entry into the air of dust from a silica process, an employer or contractor shall, where it is practicable, provide for the isolation of workers from the air containing the dust.
Section 353 Personal protective equipment
353. (1) An employer or contractor shall provide, and require a worker to wear, a respiratory protective device and other personal protective equipment that meet the requirements of Part VII where:
(a) the protective measures required by section 351 or 352 are not practicable; or
(b) the worker is employed in cleaning and maintenance work and may be exposed to dust from a silica process.
(2) For workers engaged in abrasive blasting, an employer or contractor shall provide and maintain approved blasting hoods supplied with air:
(a) of a volume of not less than 170 litres per minute at a pressure of not more than 140 kilopascals; and
(b) that is clean and at a reasonable temperature.
(3) For workers who may be exposed to dust resulting from abrasive blasting, an employer or contractor shall provide and maintain respiratory protective devices that meet the requirements of Part VII.
Section 354 Standards for blasting enclosures
354. (1) An employer or contractor shall ensure that every blasting enclosure is:
(a) constructed, operated and maintained to prevent the escape of dust;
(b) provided with an efficient, dust-extraction system, that is operated continuously whenever the blasting enclosure is in use, whether or not abrasive blasting is actually taking place; and
(c) provided with efficient equipment for separating the abrasive from the dust, to the extent that is practicable.
(2) An employer or contractor shall ensure that an abrasive is not reintroduced into a blasting apparatus until the abrasive has been separated from the dust pursuant to clause (1)(c).
(3) An employer or contractor shall ensure that:
(a) a blasting enclosure is inspected daily when in use;
(b) a blasting enclosure, the equipment connected with the enclosure and the ventilating system associated with the enclosure are thoroughly examined and tested regularly by a competent person; and
(c) all defects identified pursuant to this section are remedied immediately.
(4) A competent person who carries out examinations and testing pursuant to clause (3)(b) shall record the results of those examinations and tests.
Section 355 Use of blasting enclosures
355. An employer or contractor shall ensure that:
(a) to the extent that is practicable, no abrasive blasting of articles that are likely to give rise to dust containing uncombined silica is done other than in a blasting enclosure;
(b) where practicable, no sand or other substance containing more than 1% by weight of uncombined silica is used for abrasive blasting in a blasting enclosure; and
(c) no work is performed in a blasting enclosure except:
(i) abrasive blasting and work immediately incidental to abrasive blasting; and
(ii) cleaning and maintenance of the blasting enclosure, the equipment associated with the blasting enclosure and the ventilation system.
Section 356 Sandblasting
356. (1) An employer or contractor shall ensure that no sandblasting is done to any article outside a blasting enclosure where it is reasonably practicable to introduce the article into a blasting enclosure.
(2) An employer or contractor shall ensure that no sandblasting is done inside any structure or confined space without:
(a) obtaining the written permission of the director; and
(b) complying with any conditions that the director may specify.
Section 357 Silica flour
357. An employer or contractor shall ensure that no silica flour is used:
(a) for any purpose for which a less hazardous substance may be substituted; or
(b) in the manufacture of scouring powder or abrasive soaps or as an abrasive in any process.
Section 358 Medical examinations
358. (1) In this section, "worker" means a worker who is regularly employed in a silica process.
(1.1) Not less than once every two years and with consent of the worker, the employer shall:
(a) offer to arrange for a medical examination of the worker during the worker's normal working hours; and
(b) reimburse the worker for any part of the cost of the medical examination that the worker cannot recover.
(2) Where a worker cannot attend a medical examination mentioned in subsection (1.1) during the worker's normal working hours, an employer shall credit the worker's attendance at the examination as time at work and ensure that the worker does not lose any pay or other benefits.
(3) A medical examination arranged pursuant to subsection (1.1) must include:
(a) a comprehensive medical history and physical examination with special attention to the respiratory system;
(b) lung-function tests, including forced vital capacity and forced expiratory volume at one second; and
(c) any further medical investigations that are necessary for the diagnosis of a silica-related disease.
[Sask. Reg. 67/2007, s. 27]
Part XXXIII Repeal, Transitional and Coming into Force
Schedule Table 21 Contamination Limits
[Sections 307 and 309, clause 346(f)]
Also check Tables 19 and 20 for substances (such as asbestos and benzene) with additional requirements
Table
| CAS Number | Substance | 8 hour average contamination limit mg/m³* or ppm* | 15 minute average contamination limit mg/m³* or ppm* | Notation+ |
| 75-07-0 | Acetaldehyde | **C25 ppm | T20 | |
| 64-19-7 | Acetic acid | 10 ppm | 15 ppm | |
| 108-24-7 | Acetic anhydride | 5 ppm | 10 ppm | |
| 67-64-1 | Acetone | 500 ppm | 750 ppm | |
| 75-86-5 | Acetone cyanohydrin, as CN | **C5 mg/m3 | Skin | |
| 75-05-8 | Acetonitrile | 20 ppm | 30 ppm | Skin |
| 98-86-2 | Acetophenone | 10 ppm | 15 ppm | |
| 79-27-6 | Acetylene tetrabromide | 1 ppm | 3 ppm | |
| 50-78-2 | Acetylsalicylic acid | 5 mg/m3 | 10 mg/m3 | |
| 107-02-8 | Acrolein | **C0.1 ppm | Skin | |
| 79-06-1 | Acrylamide (inhalable fraction++ and vapour) | 0.03 mg/m3 | 0.09 mg/m3 | T20, Skin |
| 79-10-7 | Acrylic acid | 2 ppm | 4 ppm | Skin |
| 107-13-1 | Acrylonitrile | 2 ppm | 4 ppm | Skin, T20 |
| 124-04-9 | Adipic acid | 5 mg/m3 | 10 mg/m3 | |
| 111-69-3 | Adiponitrile | 2 ppm | 4 ppm | Skin |
| 309-00-2 | Aldrin | 0.25 mg/m3 | 0.75 mg/m3 | Skin |
| Aliphatic hydrocarbon gases, Alkane [C1-C4] | 1000 ppm | 1250 ppm | ||
| 107-18-6 | Allyl alcohol | 0.5 ppm | 1.5 ppm | Skin |
| 107-05-1 | Allyl chloride | 1 ppm | 2 ppm | |
| 106-92-3 | Allyl glycidyl ether (AGE) | 1 ppm | 3 ppm | |
| 2179-59-1 | Allyl propyl disulphide | 0.5 ppm | 1.5 ppm | SEN |
| 7429-90-5 | Aluminum and compounds (as Al): | |||
| Metal dust | 10 mg/m3 | 20 mg/m3 | ||
| Pyro powders | 5 mg/m3 | 10 mg/m3 | ||
| Soluble salts | 2 mg/m3 | 4 mg/m3 | ||
| Alkyls, not otherwise specified | 2 mg/m3 | 4 mg/m3 | ||
| 1344-28-1 | Aluminum oxide | 10 mg/m3 | 20 mg/m3 | |
| 504-29-0 | 2-Aminopyridine | 0.5 ppm | 1.0 ppm | |
| 61-82-5 | Amitrole | 0.2 mg/m3 | 0.6 mg/m3 | T20 |
| 7664-41-7 | Ammonia | 25 ppm | 35 ppm | |
| 12125-02-9 | Ammonium chloride fume | 10 mg/m3 | 20 mg/m3 | |
| 3825-26-1 | Ammonium perfluorooctanoate | 0.01 mg/m3 | 0.03 mg/m3 | Skin |
| 7773-06-0 | Ammonium sulphamate (Ammate) | 10 mg/m3 | 20 mg/m3 | |
| 994-05-8 | tert-Amyl methyl ether (TAME) | 20 ppm | 30 ppm | |
| 62-53-3 | Aniline | 2 ppm | 4 ppm | Skin |
| 90-04-0 | o-Anisidine | 0.5 mg/m3 | 1.5 mg/m3 | Skin, T20 |
| 104-94-9 | p-Anisidine | 0.5 mg/m3 | 1.5 mg/m3 | Skin |
| 7440-36-0 | Antimony and compounds, (as Sb) | 0.5 mg/m3 | 1.5 mg/m3 | |
| 86-88-4 | ANTU (alpha-Naphthyl thiourea) | 0.3 mg/m3 | 0.9 mg/m3 | |
| 7440-38-2 | Arsenic, and inorganic compounds, (as As) | 0.01 mg/m3 | 0.03 mg/m3 | T20 |
| 7784-42-1 | Arsine | 0.05 ppm | 0.15 ppm | |
| 8052-42-4 | Asphalt (bitumen) fume, as benzene soluble aerosol (inhalable fraction++) | 0.5 mg/m3 | 1.5 mg/m3 | |
| 1912-24-9 | Atrazine | 5 mg/m3 | 10 mg/m3 | T20 |
| 86-50-0 | Azinphos-methyl (inhalable fraction++ and vapour) | 0.2 mg/m3 | 0.6 mg/m3 | Skin; SEN |
| 7440-39-3 | Barium and soluble compounds, (as Ba) | 0.5 mg/m3 | 1.5 mg/m3 | |
| 7727-43-7 | Barium sulphate | 10 mg/m3 | 20 mg/m3 | |
| 17804-35-2 | Benomyl | 10 mg/m3 | 20 mg/m3 | |
| 98-07-7 | Benzotrichloride | **C0.1 ppm | Skin, T20 | |
| 98-88-4 | Benzoyl chloride | **C0.5 ppm | T20 | |
| 94-36-0 | Benzoyl peroxide | 5 mg/m3 | 10 mg/m3 | |
| 140-11-4 | Benzyl acetate | 10 ppm | 20 ppm | |
| 100-44-7 | Benzyl chloride | 1 ppm | 2 ppm | T20 |
| 7440-41-7 | Beryllium and compounds, (as Be) | 0.002 mg/m3 | 0.01 mg/m3 | T20 |
| 92-52-4 | Biphenyl (diphenyl) | 0.2 ppm | 0.6 ppm | |
| 3033-62-3 | Bis (2-dimethylaminoethyl)ether (DMAEE) | 0.05 ppm | 0.15 ppm | Skin |
| 1304-82-1 | Bismuth telluride | |||
| Undoped | 10 mg/m3 | 20 mg/m3 | ||
| Se-doped, as Bi2Te3 | 5 mg/m3 | 10 mg/m3 | ||
| 1330-43-4; 1303-96-4; 10043-35-3; 12179-04-3 | Borate compounds, inorganic (inhalable fraction++) | 2 mg/m3 | 6 mg/m3 | |
| 1303-86-2 | Boron oxide | 10 mg/m3 | 20 mg/m3 | |
| 10294-33-4 | Boron tribromide | **C1 ppm | ||
| 7637-07-2 | Boron trifluoride | **C1 ppm | ||
| 314-40-9 | Bromacil | 10 mg/m3 | 20 mg/m3 | |
| 7726-95-6 | Bromine | 0.1 ppm | 0.2 ppm | |
| 7789-30-2 | Bromine pentafluoride | 0.1 ppm | 0.3 ppm | |
| 74-97-5 | Bromochloromethane (Chlorobromomethane) | 200 ppm | 250 ppm | |
| 75-25-2 | Bromoform | 0.5 ppm | 1.5 ppm | Skin |
| 106-94-5 | 1-Bromopropane | 10 ppm | 20 ppm | |
| 106-99-0 | 1,3-Butadiene | 2 ppm | 4 ppm | T20 |
| 106-97-8; 75-28-5 | Butane, All isomers | See Aliphatic hydrocarbon gases [C1-C4] | ||
| 111-76-2 | 2-Butoxyethanol (Butyl Cellosolve or EGBE) | 20 ppm | 30 ppm | |
| 112-07-2 | 2-Butoxyethyl acetate (EGBEA) | 20 ppm | 30 ppm | |
| 123-86-4 | n-Butyl acetate | 150 ppm | 200 ppm | |
| 105-46-4 | sec-Butyl acetate | 200 ppm | 250 ppm | |
| 540-88-5 | tert-Butyl acetate | 200 ppm | 250 ppm | |
| 141-32-2 | n-Butyl acrylate | 2 ppm | 4 ppm | SEN |
| 71-36-3 | n-Butyl alcohol (n-butanol) | 20 ppm | 30 ppm | |
| 78-92-2 | sec-Butyl alcohol (sec-butanol) | 100 ppm | 125 ppm | |
| 75-65-0 | tert-Butyl alcohol (tert-butanol) | 100 ppm | 125 ppm | |
| 109-73-9 | n-Butylamine | **C5 ppm | Skin | |
| 1189-85-1 | tert-Butyl chromate, (as Cr03) | **C0.1 mg/m3 | Skin | |
| 2426-08-6 | n-Butyl glycidyl ether (BGE) | 3 ppm | 6 ppm | Skin, SEN |
| 138-22-7 | n-Butyl lactate | 5 ppm | 10 ppm | |
| 109-79-5 | n-Butyl mercaptan | 0.5 ppm | 1.5 ppm | |
| 89-72-5 | o-sec-Butylphenol | 5 ppm | 7 ppm | Skin |
| 98-51-1 | p-tert-Butyltoluene | 1 ppm | 2 ppm | |
| 7440-43-9 | Cadmium, and compounds, (as Cd): | T20 | ||
| (total fraction) | 0.01 mg/m3 | 0.03 mg/m3 | ||
| (respirable fraction++) | 0.002 mg/m3 | 0.006 mg/m3 | ||
| 1317-65-3 | Calcium carbonate | 10 mg/m3 | 20 mg/m3 | |
| 13765-19-0 | Calcium chromate, (as Cr) | 0.001 mg/m3 | 0.003 mg/m3 | |
| 156-62-7 | Calcium cyanamide | 0.5 mg/m3 | 1.5 mg/m3 | |
| 1305-62-0 | Calcium hydroxide | 5 mg/m3 | 10 mg/m3 | |
| 1305-78-8 | Calcium oxide | 2 mg/m3 | 4 mg/m3 | |
| 1344-95-2 | Calcium silicate, synthetic nonfibrous | 10 mg/m3 | 20 mg/m3 | |
| 76-22-2 | Camphor, synthetic | 2 ppm | 3 ppm | |
| 105-60-2 | Caprolactam (inhalable fraction++ and vapour) | 5 mg/m3 | 10 mg/m3 | |
| 2425-06-1 | Captafol | 0.1 mg/m3 | 0.3 mg/m3 | Skin, T20 |
| 133-06-2 | Captan (inhalable fraction++) | 5 mg/m3 | 10 mg/m3 | SEN |
| 63-25-2 | Carbaryl | 5 mg/m3 | 10 mg/m3 | |
| 1563-66-2 | Carbofuran (inhalable fraction++ and vapour) | 0.1 mg/m3 | 0.3 mg/m3 | |
| 1333-86-4 | Carbon black | 3.5 mg/m3 | 7 mg/m3 | |
| 124-38-9 | Carbon dioxide | 5000 ppm | 30,000 ppm | |
| 75-15-0 | Carbon disulphide | 10 ppm | 15 ppm | Skin |
| 630-08-0 | Carbon monoxide | 25 ppm | 190 ppm | |
| 558-13-4 | Carbon tetrabromide | 0.1 ppm | 0.3 ppm | |
| 75-44-5 | Carbonyl chloride (Phosgene) | 0.1 ppm | 0.3 ppm | |
| 353-50-4 | Carbonyl fluoride | 2 ppm | 5 ppm | |
| 120-80-9 | Catechol (Pyrocatechol) | 5 ppm | 7.8 ppm | Skin |
| 9004-34-6 | Cellulose (paper fibre) | 10 mg/m3 | 20 mg/m3 | |
| 21351-79-1 | Cesium hydroxide | 2 mg/m3 | 4 mg/m3 | |
| 57-74-9 | Chlordane | 0.5 mg/m3 | 1.5 mg/m3 | Skin |
| 8001-35-2 | Chlorinated camphene | 0.5 mg/m3 | 1 mg/m3 | Skin, T20 |
| 31242-93-0 | o-Chlorinated diphenyl oxide | 0.5 mg/m3 | 1.5 mg/m3 | |
| 7782-50-5 | Chlorine | 0.5 ppm | 1 ppm | |
| 10049-04-4 | Chlorine dioxide | 0.1 ppm | 0.3 ppm | |
| 7790-91-2 | Chlorine trifluoride | **C 0.1 ppm | ||
| 107-20-0 | Chloroacetaldehyde | **C1 ppm | ||
| 78-95-5 | Chloroacetone | **C1 ppm | Skin | |
| 532-27-4 | alpha-Chloroacetophenone (Phenacyl chloride) | 0.05 ppm | 0.15 ppm | |
| 79-04-9 | Chloroacetyl chloride | 0.05 ppm | 0.15 ppm | Skin |
| 108-90-7 | Chlorobenzene (Monochlorobenzene) | 10 ppm | 15 ppm | |
| 2698-41-1 | o-Chlorobenzylidene malononitrile | **C0.05 ppm | Skin | |
| 126-99-8 | 2-Chloro-1,3-butadiene (beta-Chloroprene) | 10 ppm | 15 ppm | Skin |
| 75-45-6 | Chlorodifluoromethane | 1000 ppm | 1250 ppm | |
| 53469-21-9 | Chlorodiphenyl (42% chlorine) | 1 mg/m3 | 3 mg/m3 | Skin |
| 11097-69-1 | Chlorodiphenyl (54% chlorine) | 0.5 mg/m3 | 1.5 mg/m3 | Skin |
| 107-07-3 | 2-Chloroethanol (Ethylene chlorohydrin) | **C1.0 ppm | Skin | |
| 600-25-9 | 1-Chloro-1-nitropropane | 2 ppm | 4 ppm | |
| 76-15-3 | Chloropentafluoroethane | 1000 ppm | 1250 ppm | |
| 76-06-2 | Chloropicrin | 0.1 ppm | 0.3 ppm | |
| 127-00-4; 78-89-7 | 1-Chloro-2-propanol and 2- Chloro-1-propanol | 1 ppm | 3 ppm | Skin |
| 598-78-7 | 2-Chloropropionic acid | 0.1 ppm | 0.3 ppm | Skin |
| 2039-87-4 | o-Chlorostyrene | 50 ppm | 75 ppm | |
| 95-49-8 | o-Chlorotoluene | 50 ppm | 65 ppm | |
| 2921-88-2 | Chlorpyrifos, (inhalable fraction++ and vapour) | 0.1 mg/m3 | 0.3 mg/m3 | Skin |
| 7440-47-3 | Chromium metal and inorganic compounds, (as Cr): | |||
| Metal and Cr (III) compounds | 0.5 mg/m3 | 1.5 mg/m3 | ||
| Water soluble Cr (VI) compounds | 0.05 mg/m3 | 0.15 mg/m3 | T20 | |
| Insoluble Cr (VI) compounds | 0.01 mg/m3 | 0.03 mg/m3 | T20 | |
| 14977-61-8 | Chromyl chloride | 0.025 ppm | 0.07 ppm | |
| 2971-90-6 | Clopidol | 10 mg/m3 | 20 mg/m3 | |
| Coal dust: | ||||
| Anthracite (respirable fraction++) | 0.4 mg/m3 | 1.2 mg/m3 | ||
| Bituminous (respirable fraction++) | 0.9 mg/m3 | 2.7 mg/m3 | ||
| 65996-93-2 | Coal tar pitch volatiles, as benzene soluble aerosol (See Particulate polycyclic aromatic hydrocarbons) | 0.2 mg/m3 | 0.6 mg/m3 | T20 |
| 7440-48-4 | Cobalt and inorganic compounds, (as Co) | 0.02 mg/m3 | 0.06 mg/m3 | T20 |
| 10210-68-1 | Cobalt carbonyl, (as Co) | 0.1 mg/m3 | 0.3 mg/m3 | |
| 16842-03-8 | Cobalt hydrocarbonyl, (as Co) | 0.1 mg/m3 | 0.3 mg/m3 | |
| 7440-50-8 | Copper, (as Cu): | |||
| fume | 0.2 mg/m3 | 0.6 mg/m3 | ||
| dusts and mists | 1 mg/m3 | 3 mg/m3 | ||
| ----- | Cotton dust, raw | 0.2 mg/m3 | 0.6 mg/m3 | |
| 1319-77-3 | Cresol, all isomers | 5 ppm | 10 ppm | Skin |
| 4170-30-3 | Crotonaldehyde | **C 0.3 ppm | Skin | |
| 299-86-5 | Crufomate | 5 mg/m3 | 10 mg/m3 | |
| 98-82-8 | Cumene | 50 ppm | 74 ppm | |
| 420-04-2 | Cyanamide | 2 mg/m3 | 4 mg/m3 | |
| 460-19-5 | Cyanogen | 10 ppm | 15 ppm | |
| 506-77-4 | Cyanogen chloride | **C0.3 ppm | ||
| 110-82-7 | Cyclohexane | 100 ppm | 150 ppm | |
| 108-93-0 | Cyclohexanol | 50 ppm | 62 ppm | Skin |
| 108-94-1 | Cyclohexanone | 20 ppm | 50 ppm | Skin |
| 110-83-8 | Cyclohexene | 300 ppm | 375 ppm | |
| 108-91-8 | Cyclohexylamine | 10 ppm | 15 ppm | |
| 121-82-4 | Cyclonite (RDX) | 0.5 mg/m3 | 1.5 mg/m3 | Skin |
| 542-92-7 | Cyclopentadiene | 75 ppm | 94 ppm | |
| 287-92-3 | Cyclopentane | 600 ppm | 900 ppm | |
| 13121-70-5 | Cyhexatin | 5 mg/m3 | 10 mg/m3 | |
| 94-75-7 | 2,4-D (2,4-Dichlorophenoxy-acetic acid) | 10 mg/m3 | 20 mg/m3 | |
| 50-29-3 | DDT (Dichlorodiphenyltrichloroethane) | 1 mg/m3 | 3 mg/m3 | T20 |
| 17702-41-9 | Decaborane | 0.05 ppm | 0.15 ppm | Skin |
| 8065-48-3 | Demeton (inhalable fraction++ and vapour) | 0.05 mg/m3 | 0.15 mg/m3 | Skin |
| 919-86-8 | Demeton-S-methyl, (inhalable fraction++ and vapour) | 0.05 mg/m3 | 0.15 mg/m3 | Skin, SEN |
| 123-42-2 | Diacetone alcohol (4-hydroxy-4- methyl-2-pentanone) | 50 ppm | 60 ppm | |
Contamination Limits/ cont'd
| CAS Number | Substance | 8 hour average contamination limit mg/m³* or ppm* | 15 minute average contamination limit mg/m³* or ppm* | Notation+ |
| 333-41-5 | Diazinon, (inhalable fraction++ and vapour) | 0.01 mg/m3 | 0.03 mg/m3 | Skin |
| 334-88-3 | Diazomethane | 0.2 ppm | 0.6 ppm | T20 |
| 19287-45-7 | Diborane | 0.1 ppm | 0.3 ppm | |
| 102-81-8 | 2-N-Dibutylaminoethanol | 0.5 ppm | 1 ppm | Skin |
| 2528-36-1 | Dibutyl phenyl phosphate | 0.3 ppm | 0.6 ppm | Skin |
| 107-66-4 | Dibutyl phosphate | 1 ppm | 2 ppm | |
| 84-74-2 | Dibutyl phthalate | 5 mg/m3 | 10 mg/m3 | |
| 79-43-6 | Dichloroacetic acid | 0.5 ppm | 1.5 ppm | Skin, T20 |
| 7572-29-4 | Dichloracetylene | **C0.1 ppm | ||
| 95-50-1 | o-Dichlorobenzene | 25 ppm | 50 ppm | |
| 106-46-7 | p-Dichlorobenzene | 10 ppm | 15 ppm | T20 |
| 764-41-0 | 1,4-Dichloro-2-butene | 0.005 ppm | 0.015 ppm | Skin, T20 |
| 75-71-8 | Dichlorodifluoromethane | 1000 ppm | 1250 ppm | |
| 118-52-5 | 1,3-Dichloro-5, 5-dimethyl hydantoin | 0.2 mg/m3 | 0.4 mg/m3 | |
| 75-34-3 | 1,1-Dichloroethane | 100 ppm | 125 ppm | |
| 540-59-0; 156-59-2; 156-60-5 | 1,2-Dichloroethylene, all isomers | 200 ppm | 250 ppm | |
| 111-44-4 | Dichloroethyl ether | 5 ppm | 10 ppm | Skin |
| 75-43-4 | Dichlorofluoromethane | 10 ppm | 15 ppm | |
| 75-09-2 | Dichloromethane | 50 ppm | 75 ppm | T20 |
| 594-72-9 | 1,1-Dichloro-1-nitroethane | 2 ppm | 4 ppm | |
| 542-75-6 | 1,3-Dichloropropene | 1 ppm | 2 ppm | Skin, T20 |
| 75-99-0 | 2,2-Dichloropropionic acid, (inhalable fraction++) | 5 mg/m3 | 10 mg/m3 | |
| 76-14-2 | Dichlorotetrafluoroethane | 1000 ppm | 1250 ppm | |
| 62-73-7 | Dichlorvos (DDVP), (inhalable fraction++ and vapour) | 0.1 mg/m3 | 0.3 mg/m3 | Skin, SEN, T20 |
| 141-66-2 | Dicrotophos, (inhalable fraction++ and vapour) | 0.05 mg/m3 | 0.15 mg/m3 | Skin |
| 77-73-6 | Dicyclopentadiene | 5 ppm | 8 ppm | |
| 102-54-5 | Dicyclopentadienyl iron | 10 mg/m3 | 20 mg/m3 | |
| 60-57-1 | Dieldrin | 0.25 mg/m3 | 0.75 mg/m3 | Skin |
| 683334-30-5; 68476-30-2; 68476-31-3; 68476-34-6; 77650-28-3 | Diesel fuel as total hydrocarbons, (vapour) | 100 mg/m3 | 150 mg/m3 | Skin |
| 111-42-2 | Diethanolamine | 2 mg/m3 | 4 mg/m3 | Skin |
| 109-89-7 | Diethylamine | 5 ppm | 15 ppm | Skin |
| 100-37-8 | 2-Diethylaminoethanol | 2 ppm | 4 ppm | Skin |
| 111-40-0 | Diethylene triamine | 1 ppm | 2 ppm | Skin |
| 96-22-0 | Diethyl ketone | 200 ppm | 300 ppm | |
| 84-66-2 | Diethyl phthalate | 5 mg/m3 | 10 mg/m3 | |
| 75-61-6 | Difluorodibromomethane | 100 ppm | 125 ppm | |
| 2238-07-5 | Diglycidyl ether (DGE) | 0.1 ppm | 0.3 ppm | |
| 108-83-8 | Diisobutyl ketone | 25 ppm | 30 ppm | |
| 108-18-9 | Diisopropylamine | 5 ppm | 7 ppm | Skin |
| 127-19-5 | N,N-Dimethylacetamide | 10 ppm | 15 ppm | Skin |
| 124-40-3 | Dimethylamine | 5 ppm | 15 ppm | |
| 121-69-7 | Dimethylaniline (N,N-Dimethylaniline) | 5 ppm | 10 ppm | Skin |
| 14857-34-2 | Dimethylethoxysilane | 0.5 ppm | 1.5 ppm | |
| 68-12-2 | Dimethylformamide | 10 ppm | 15 ppm | Skin, T20 |
| 57-14-7 | 1,1-Dimethylhydrazine | 0.01 ppm | 0.03 ppm | Skin, T20 |
| 131-11-3 | Dimethylphthalate | 5 mg/m3 | 10 mg/m3 | |
| 77-78-1 | Dimethyl sulphate | 0.1 ppm | 0.3 ppm | Skin, T20 |
| 75-18-3 | Dimethyl sulphide | 10 ppm | 20 ppm | |
| 148-01-6 | Dinitolmide | 5 mg/m3 | 10 mg/m3 | |
| 528-29-0; 99-65-0; 100-25-4; 25154-54-5 | Dinitrobenzene (all isomers) | 0.15 ppm | 0.30 ppm | Skin |
| 534-52-1 | Dinitro-o-cresol | 0.2 mg/m3 | 0.6 mg/m3 | Skin |
| 25321-14-6 | Dinitrotoluene | 0.2 mg/m3 | 0.6 mg/m3 | Skin, T20 |
| 123-91-1 | 1,4-Dioxane | 20 ppm | 30 ppm | Skin, T20 |
| 78-34-2 | Dioxathion (inhalable fraction++ and vapour) | 0.1 mg/m3 | 0.3 mg/m3 | Skin |
| 646-06-0 | 1,3-Dioxolane | 20 ppm | 30 ppm | |
| 122-39-4 | Diphenylamine | 10 mg/m3 | 20 mg/m3 | |
| 34590-94-8 | Dipropylene glycol methyl ether (DPGME) | 100 ppm | 150 ppm | Skin |
| 123-19-3 | Dipropyl ketone | 50 ppm | 60 ppm | |
| 2764-72-9; | Diquat: | |||
| 85-00-7; | (inhalable fraction++) | 0.5 mg/m3 | 1.5 mg/m3 | Skin |
| 6385-62-2 | (respirable fraction++) | 0.1 mg/m3 | 0.3 mg/m3 | Skin |
| 117-81-7 | Di-sec, octyl phthalate (Di-2- ethylhexyl phthalate or DEHP) | 5 mg/m3 | 10 mg/m3 | T20 |
| 97-77-8 | Disulphiram | 2 mg/m3 | 4 mg/m3 | |
| 298-04-4 | Disulphoton, (inhalable fraction++ and vapour) | 0.05 mg/m3 | 0.15 mg/m3 | Skin |
| 128-37-0 | 2,6-Di-tert-butyl-p-cresol (butylated hydroxytoluene or BHT) (inhalable fraction++ and vapour) | 2 mg/m3 | 4 mg/m3 | |
| 330-54-1 | Diuron | 10 mg/m3 | 20 mg/m3 | |
| 1321-74-0 | Divinyl benzene | 10 ppm | 15 ppm | |
| 112-55-0 | Dodecyl mercaptan | 0.1 ppm | 0.3 ppm | SEN |
| 1302-74-5 | Emery | 10 mg/m3 | 20 mg/m3 | |
| 115-29-7 | Endosulphan | 0.1 mg/m3 | 0.3 mg/m3 | Skin |
| 72-20-8 | Endrin | 0.1 mg/m3 | 0.3 mg/m3 | Skin |
| 13838-16-9 | Enflurane | 75 ppm | 100 ppm | |
| 106-89-8 | Epichlorohydrin | 0.5 ppm | 1.5 ppm | Skin, T20 |
| 2104-64-5 | EPN (inhalable fraction++) | 0.1 mg/m3 | 0.3 mg/m3 | Skin |
| 74-84-0 | Ethane | See Aliphatic hydrocarbon gases [C1-C4] | ||
| 64-17-5 | Ethanol | 1000 ppm | 1250 ppm | |
| 141-43-5 | Ethanolamine | 3 ppm | 6 ppm | |
| 563-12-2 | Ethion, (inhalable fraction++ and vapour) | 0.05 mg/m3 | 0.15 mg/m3 | Skin |
| 110-80-5 | 2-Ethoxyethanol (Glycol monoethyl ether) | 5 ppm | 7 ppm | Skin |
| 111-15-9 | 2-Ethyoxyethyl acetate (Cellosolve acetate) | 5 ppm | 8 ppm | Skin |
| 141-78-6 | Ethyl acetate | 400 ppm | 500 ppm | |
| 140-88-5 | Ethyl acrylate | 5 ppm | 15 ppm | T20 |
| 75-04-7 | Ethylamine | 5 ppm | 15 ppm | Skin |
| 541-85-5 | Ethyl amyl ketone (5-Methyl-3- heptanone) | 25 ppm | 30 ppm | |
| 100-41-4 | Ethyl benzene | 100 ppm | 125 ppm | T20 |
| 74-96-4 | Ethyl bromide | 5 ppm | 7 ppm | Skin |
| 637-92-3 | Ethyl tert-butyl ether | 5 ppm | 10 ppm | |
| 106-35-4 | Ethyl butyl ketone (3-Heptanone) | 50 ppm | 75 ppm | |
| 75-00-3 | Ethyl chloride | 100 ppm | 125 ppm | Skin |
| 7085-85-0 | Ethyl cyanoacrylate | 0.2 ppm | 0.6 ppm | |
| 74-85-1 | Ethylene | 200 ppm | 250 ppm | |
| 107-15-3 | Ethylenediamine | 10 ppm | 15 ppm | Skin |
| 107-06-2 | Ethylene dichloride | 10 ppm | 20 ppm | |
| 107-21-1 | Ethylene glycol, (as an aerosol) | **C 100 mg/m3 | ||
| 628-96-6 | Ethylene glycol dinitrate (EGDN) | 0.05 ppm | 0.15 ppm | Skin |
| 75-21-8 | Ethylene oxide | 1 ppm | 2 ppm | T20 |
| 151-56-4 | Ethylenimine | 0.5 ppm | 1.5 ppm | Skin, T20 |
| 60-29-7 | Ethyl ether | 400 ppm | 500 ppm | |
| 109-94-4 | Ethyl formate | 100 ppm | 150 ppm | |
| 149-57-5 | 2-Ethylhexanoic acid, (inhalable fraction++ and vapour) | 5 mg/m3 | 10 mg/m3 | |
| 16219-75-3 | Ethylidene norbornene | **C5 ppm | ||
| 75-08-1 | Ethyl mercaptan | 0.5 ppm | 1.5 ppm | |
| 100-74-3 | N-Ethylmorpholine | 5 ppm | 8 ppm | Skin |
| 78-10-4 | Ethyl silicate | 10 ppm | 15 ppm | |
| 22224-92-6 | Fenamiphos | 0.1 mg/m3 | 0.3 mg/m3 | Skin |
| 115-90-2 | Fensulphothion (inhalable fraction++ and vapour) | 0.01 mg/m3 | 0.03 mg/m3 | Skin |
| 55-38-9 | Fenthion | 0.2 mg/m3 | 0.6 mg/m3 | Skin |
| 14484-64-1 | Ferbam | 10 mg/m3 | 20 mg/m3 | |
| 12604-58-9 | Ferrovanadium dust | 1 mg/m3 | 3 mg/m3 | |
| Flour dust | 3 mg/m3 | 6 mg/m3 | SEN | |
| ------- | Fluoride, (as F) | 2.5 mg/m3 | 5 mg/m3 | |
| 7782-41-4 | Fluorine | 1 ppm | 2 ppm | |
| 944-22-9 | Fonofos | 0.1 mg/m3 | 0.3 mg/m3 | Skin |
| 50-00-0 | Formaldehyde | **C0.3 ppm | SEN, T20 | |
| 75-12-7 | Formamide | 10 ppm | 15 ppm | Skin |
| 64-18-6 | Formic acid | 5 ppm | 10 ppm | |
| 98-01-1 | Furfural | 2 ppm | 4 ppm | Skin |
| 98-00-0 | Furfuryl alcohol | 10 ppm | 15 ppm | Skin |
| 1303-00-0 | Gallium arsenide (respirable fraction++) | 0.0003 mg/m3 | 0.0009 mg/m3 | |
| 86290-81-5 | Gasoline | 300 ppm | 500 ppm | |
| 7782-65-2 | Germanium tetrahydride | 0.2 ppm | 0.6 ppm | |
| 111-30-8 | Glutaraldehyde, activated and inactivated | **C0.05 ppm | SEN | |
| 56-81-5 | Glycerin mist | 10 mg/m3 | 20 mg/m3 | |
| 556-52-5 | Glycidol | 2 ppm | 4 ppm | |
| 107-22-2 | Glyoxal, (inhalable fraction++ and vapour) | 0.1 mg/m3 | 0.3 mg/m3 | SEN |
| ------- | Grain dust (oat, wheat, barley) | 4 mg/m3 | 8 mg/m3 | |
| 7782-42-5 | Graphite, natural-all forms except graphite fibres (respirable fraction++) | 2 mg/m3 | 4 mg/m3 | |
| 7778-18-9 | Gypsum (Calcium sulphate) | 10 mg/m3 | 20 mg/m3 | |
| 7440-58-6 | Hafnium and compounds, (as Hf) | 0.5 mg/m3 | 1.5 mg/m3 | |
| 151-67-7 | Halothane | 50 ppm | 60 ppm | |
| 76-44-8; 1024-57-3 | Heptachlor and Heptchlor epoxide | 0.05 mg/m3 | 0.15 mg/m3 | Skin, T20 |
| 142-82-5 | Heptane (n-Heptane) | 400 ppm | 500 ppm | |
| 118-74-1 | Hexachlorobenzene | 0.002 mg/m3 | 0.006 mg/m3 | Skin, T20 |
| 87-68-3 | Hexachlorobutadiene | 0.02 ppm | 0.06 ppm | Skin, T20 |
| 77-47-4 | Hexachlorocyclopentadiene | 0.01 ppm | 0.03 ppm | |
| 67-72-1 | Hexachloroethane | 1 ppm | 2 ppm | Skin, T20 |
| 1335-87-1 | Hexachloronaphthalene | 0.2 mg/m3 | 0.6 mg/m3 | Skin |
| 684-16-2 | Hexafluoroacetone | 0.1 ppm | 0.3 ppm | Skin |
| 85-42-7; 13149-00-3; 14166-21-3 | Hexahydrophthalic anhydride, (inhalable fraction++ and vapour), all isomers | **C0.005 mg/m3 | SEN | |
| 822-06-0 | Hexamethylene diisocyanate | 0.005 ppm | 0.015 ppm | |
| 110-54-3 | Hexane (n-Hexane) | 50 ppm | 62.5 ppm | Skin |
| ---------- | Hexane (other isomers) | 500 ppm | 1000 ppm | |
| 124-09-4 | Hexanediamine | 0.5 ppm | 1.0 ppm | |
| 592-41-6 | 1-Hexene | 50 ppm | 75 ppm | |
| 108-84-9 | sec-Hexyl acetate | 50 ppm | 60 ppm | |
| 107-41-5 | Hexylene glycol | **C25 ppm | ||
| 302-01-2 | Hydrazine | 0.01 ppm | 0.03 ppm | Skin, T20 |
| 61788-32-7 | Hydrogenated terphenyls (nonirradiated) | 0.5 ppm | 1.5 ppm | |
| 10035-10-6 | Hydrogen bromide | **C2 ppm | ||
| 7647-01-0 | Hydrogen chloride | **C2 ppm | ||
| Hydrogen cyanide and cyanide salts, (as CN): | ||||
| 74-90-8 | Hydrogen cyanide | **C4.7 ppm | Skin | |
| 592-01-8; 151-50-8; 143-33-9 | Cyanide salts | **C 5 mg/m3 | Skin | |
| 7664-39-3 | Hydrogen fluoride, (as F) | 0.5 ppm | **C 2 ppm | |
Contamination Limits / cont'd
| CAS Number | Substance | 8 hour average contamination limit mg/m³* or ppm* | 15 minute average contamination limit mg/m³* or ppm* | Notation+ |
| 7722-84-1 | Hydrogen peroxide | 1 ppm | 2 ppm | |
| 7783-07-5 | Hydrogen selenide, (as Se) | 0.05 ppm | 0.15 ppm | |
| 7783-06-4 | Hydrogen sulphide | 10 ppm | 15 ppm | |
| 123-31-9 | Hydroquinone | 2 mg/m3 | 4 mg/m3 | |
| 999-61-1 | 2-Hydroxypropyl acrylate | 0.5 ppm | 1 ppm | Skin, SEN |
| 95-13-6 | Indene | 10 ppm | 15 ppm | |
| 7440-74-6 | Indium and Compounds, (as In) | 0.1 mg/m3 | 0.3 mg/m3 | T20 (Indium pho-sphide) |
| 7553-56-2 | Iodine | **C0.1 ppm | ||
| 75-47-8 | Iodoform | 0.6 ppm | 1.2 ppm | |
| 1309-37-1 | Iron oxide fume, (dust and fume) (Fe2O3, as Fe) | 5 mg/m3 | 10 mg/m3 | |
| 13463-40-6 | Iron pentacarbonyl, (as Fe) | 0.1 ppm | 0.2 ppm | |
| ---------- | Iron salts, soluble, (as Fe) | 1 mg/m3 | 3 mg/m3 | |
| 123-51-3 | Isoamyl alcohol | 100 ppm | 125 ppm | |
| 110-19-0 | Isobutyl acetate | 150 ppm | 188 ppm | |
| 78-83-1 | Isobutyl alcohol | 50 ppm | 60 ppm | |
| 542-56-3 | Isobutyl nitrite, (inhalable fraction++ and vapour) | **C1 ppm | ||
| 26952-21-6 | Isooctyl alcohol | 50 ppm | 60 ppm | Skin |
| 78-59-1 | Isophorone | **C5 ppm | ||
| 4098-71-9 | Isophorone diisocyanate | 0.005 ppm | 0.015 ppm | |
| 109-59-1 | 2-Isopropoxyethanol | 25 ppm | 38 ppm | Skin |
| 108-21-4 | Isopropyl acetate | 100 ppm | 200 ppm | |
| 67-63-0 | Isopropyl alcohol | 200 ppm | 400 ppm | |
| 75-31-0 | Isopropylamine | 5 ppm | 10 ppm | |
| 768-52-5 | N-Isopropylaniline | 2 ppm | 4 ppm | Skin |
| 108-20-3 | Isopropyl ether | 250 ppm | 310 ppm | |
| 4016-14-2 | Isopropyl glycidyl ether (IGE) | 50 ppm | 75 ppm | |
| 1332-58-7 | Kaolin (respirable fraction++) | 2 mg/m3 | 4 mg/m3 | |
| 8008-20-6; 64742-81-0 | Kerosene /Jet fuels, as total hydrocarbon vapour | 200 mg/m3 | 250 mg/m3 | Skin |
| 463-51-4 | Ketene | 0.5 ppm | 1.5 ppm | |
| 7439-92-1 | Lead and inorganic compounds, (as Pb) | 0.05 mg/m3 | 0.15 mg/m3 | T20 |
| 3687-31-8 | Lead arsenate, (as Pb3(AsO4)2) | 0.15 mg/m3 | 0.45 mg/m3 | |
| 7758-97-6 | Lead chromate, (as Pb) | 0.05 mg/m3 | 0.15 mg/m3 | T20 |
| 7758-97-6 | Lead chromate, (as Cr) | 0.012 mg/m3 | 0.036 mg/m3 | T20 |
| 1317-65-3; 471-34-1 | Limestone (calcium carbonate) | 10 mg/m3 | 20 mg/m3 | |
| 58-89-9 | Lindane | 0.5 mg/m3 | 1.5 mg/m3 | Skin |
| 7580-67-8 | Lithium hydride | 0.025 mg/m3 | 0.075 mg/m3 | |
| 68476-85-7 | L.P.G. (liquified petroleum gas) | See Aliphatic hydrocarbon gases [C1-C4] | ||
| 546-93-0 | Magnesite | 10 mg/m3 | 20 mg/m3 | |
| 1309-48-4 | Magnesium oxide (inhalable fraction++) | 10 mg/m3 | 20 mg/m3 | |
| 121-75-5 | Malathion, (inhalable fraction++ and vapour) | 1 mg/m3 | 3 mg/m3 | Skin |
| 108-31-6 | Maleic anhydride | 0.1 ppm | 0.3 ppm | SEN |
| 7439-96-5 | Manganese and inorganic compounds, (as Mn) | 0.2 mg/m3 | 0.6 mg/m3 | |
| 12079-65-1 | Manganese cyclopentadienyl tricarbonyl, (as Mn) | 0.1 mg/m3 | 0.3 mg/m3 | Skin |
| 7439-97-6 | Mercury, (as Hg): | |||
| Alkyl compounds | 0.01 mg/m3 | 0.03 mg/m3 | Skin | |
| Aryl compounds | 0.1 mg/m3 | 0.3 mg/m3 | Skin | |
| Inorganic forms, including metallic mercury | 0.025 mg/m3 | 0.075 mg/m3 | Skin | |
| 141-79-7 | Mesityl oxide | 15 ppm | 25 ppm | |
| 79-41-4 | Methacrylic acid | 20 ppm | 30 ppm | |
| 74-82-8 | Methane | See Aliphatic hydrocarbon gases [C1-C4] | ||
| 16752-77-5 | Methomyl | 2.5 mg/m3 | 5 mg/m3 | |
| 72-43-5 | Methoxychlor | 10 mg/m3 | 20 mg/m3 | |
| 109-86-4 | 2-Methoxyethanol (Methylcellosolve-EGME) | 5 ppm | 8 ppm | Skin |
| 110-49-6 | 2-Methoxyethyl acetate (Methyl cellosolve acetate-EGMEA) | 5 ppm | 8 ppm | Skin |
| 150-76-5 | 4-Methoxyphenol | 5 mg/m3 | 10 mg/m3 | |
| 79-20-9 | Methyl acetate | 200 ppm | 250 ppm | |
| 74-99-7 | Methyl acetylene | 1000 ppm | 1250 ppm | |
| 59355-75-8 | Methyl acetylene-propadiene mixture (MAPP) | 1000 ppm | 1250 ppm | |
| 96-33-3 | Methyl acrylate | 2 ppm | 4 ppm | Skin, SEN |
| 126-98-7 | Methylacrylonitrile | 1 ppm | 2 ppm | Skin |
| 109-87-5 | Methylal (dimethoxy methane) | 1000 ppm | 1250 ppm | |
| 67-56-1 | Methyl alcohol (methanol) | 200 ppm | 250 ppm | Skin |
| 74-89-5 | Methylamine | 5 ppm | 15 ppm | |
| 110-43-0 | Methyl n-amyl ketone (2-Heptanone) | 50 ppm | 60 ppm | |
| 100-61-8 | N-Methylaniline | 0.5 ppm | 1 ppm | Skin |
| 74-83-9 | Methyl bromide | 1 ppm | 3 ppm | Skin |
| 1634-04-4 | Methyl tert-butyl ether (MTBE) | 50 ppm | 75 ppm | |
| 591-78-6 | Methyl n-butyl ketone | 5 ppm | 10 ppm | Skin |
| 74-87-3 | Methyl chloride | 50 ppm | 100 ppm | Skin |
| 137-05-3 | Methyl 2-cyanoacrylate | 0.2 ppm | 0.6 ppm | |
| 108-87-2 | Methylcyclohexane | 400 ppm | 500 ppm | |
| 25639-42-3 | Methylcyclohexanol | 50 ppm | 60 ppm | |
| 583-60-8 | o-Methylcyclohexanone | 50 ppm | 75 ppm | Skin |
| 12108-13-3 | 2-Methylcyclopentadienyl manganese tricarbonyl, (as Mn) | 0.2 mg/m3 | 0.6 mg/m3 | Skin |
| 8022-00-2 | Methyl demeton | 0.5 mg/m3 | 1.5 mg/m3 | Skin |
| 101-68-8 | Methylene bisphenyl isocyanate (MDI) | 0.005 ppm | 0.015 ppm | |
| 101-14-4 | 4,4'-Methylene bis (2-chloroaniline) (MBOCA, MOCA) | 0.01 ppm | 0.03 ppm | Skin, T20 |
| 5124-30-1 | Methylene bis (4-cyclohexylisocyanate) | 0.005 ppm | 0.015 ppm | |
| 75-09-2 | Methylene choride (dichloromethane) | 50 ppm | 63 ppm | |
| 101-77-9 | 4,4'-Methylene dianiline | 0.1 ppm | 0.3 ppm | Skin, T20 |
| 78-93-3 | Methyl ethyl ketone (MEK) | 200 ppm | 300 ppm | |
| 1338-23-4 | Methyl ethyl ketone peroxide | **C0.2 ppm | ||
| 107-31-3 | Methyl formate | 100 ppm | 150 ppm | |
| 60-34-4 | Methyl hydrazine | 0.01 ppm | 0.03 ppm | Skin, T20 |
| 74-88-4 | Methyl iodide | 2 ppm | 4 ppm | Skin, T20 |
| 110-12-3 | Methyl isoamyl ketone | 50 ppm | 60 ppm | |
| 108-11-2 | Methyl isobutyl carbinol | 25 ppm | 40 ppm | Skin |
| 108-10-1 | Methyl isobutyl ketone | 50 ppm | 75 ppm | |
| 624-83-9 | Methyl isocyanate | 0.02 ppm | 0.06 ppm | Skin |
| 563-80-4 | Methyl isopropyl ketone | 200 ppm | 250 ppm | |
| 74-93-1 | Methyl mercaptan | 0.5 ppm | 1.5 ppm | |
| 80-62-6 | Methyl methacrylate | 50 ppm | 100 ppm | SEN |
| 298-00-0 | Methyl parathion | 0.2 mg/m3 | 0.6 mg/m3 | Skin |
| 107-87-9 | Methyl propyl ketone | 200 ppm | 250 ppm | |
| 681-84-5 | Methyl silicate | 1 ppm | 2 ppm | |
| 98-83-9 | alpha-Methyl styrene | 50 ppm | 100 ppm | |
| 78-94-4 | Methyl vinyl ketone | **C0.2 ppm | Skin, SEN | |
| 21087-64-9 | Metribuzin | 5 mg/m3 | 10 mg/m3 | |
| 7786-34-7 | Mevinphos (inhalable fraction++ and vapour) | 0.01mg/m3 | 0.03 mg/m3 | Skin |
| 12001-26-2 | Mica (respirable fraction++) | 3 mg/m3 | 6 mg/m3 | |
| 7439-98-7 | Molybdenum, (as Mo): | |||
| Soluble compounds, (respirable fraction++) | 0.5 mg/m3 | 1.5 mg/m3 | ||
| Metal and insoluble compounds, (inhalable fraction++) | 10 mg/m3 | 20 mg/m3 | ||
| Metal and insoluble compounds, (respirable fraction++) | 3 mg/m3 | 6 mg/m3 | ||
| 6923-22-4 | Monocrotophos (inhalable fraction++ and vapour) | 0.05 mg/m3 | 0.15 mg/m3 | Skin |
| 110-91-8 | Morpholine | 20 ppm | 30 ppm | Skin |
| 300-76-5 | Naled, (inhalable fraction++ and vapour) | 0.1 mg/m3 | 0.3 mg/m3 | Skin, SEN |
| 91-20-3 | Naphthalene | 10 ppm | 15 ppm | Skin |
| 8006-14-2 | Natural gas | See Aliphatic hydrocarbon gases: Alkane [C1-C4] | ||
| 9006-04-6 | Natural rubber latex (as total proteins), (inhalable fraction++) | 0.001 mg/m3 | 0.003 mg/m3 | Skin, SEN |
| 7440-02-0 | Nickel, (as Ni): | |||
| Elemental (inhalable fraction++) | 1.5 mg/m3 | 3 mg/m3 | T20 | |
| Soluble inorganic compounds, (not otherwise specified) (inhalable fraction++) | 0.1 mg/m3 | 0.3 mg/m3 | ||
| Insoluble inorganic, (as not otherwise specified) (inhalable fraction++) | 0.2 mg/m3 | 0.6 mg/m3 | ||
| 12035-72-2 | Nickel subsulphide, (as Ni), (inhalable fraction++) | 0.1 mg/m3 | 0.3 mg/m3 | T20 |
| 13463-39-3 | Nickel carbonyl, (as Ni) | 0.05 ppm | 0.15 ppm | |
| 54-11-5 | Nicotine | 0.5 mg/m3 | 1.5 mg/m3 | Skin |
| 1929-82-4 | Nitrapyrin | 10 mg/m3 | 20 mg/m3 | |
| 7697-37-2 | Nitric acid | 2 ppm | 4 ppm | |
| 10102-43-9 | Nitric oxide | 25 ppm | 38 ppm | |
| 100-01-6 | p-Nitroaniline | 3 mg/m3 | 6 mg/m3 | Skin |
| 98-95-3 | Nitrobenzene | 1 ppm | 2 ppm | Skin |
| 100-00-5 | p-Nitrochlorobenzene | 0.1 ppm | 0.3 ppm | Skin |
| 79-24-3 | Nitroethane | 100 ppm | 125 ppm | |
| 10102-44-0 | Nitrogen dioxide | 3 ppm | 5 ppm | |
| 7783-54-2 | Nitrogen trifluoride | 10 ppm | 20 ppm | |
| 55-63-0 | Nitroglycerin (NG) | 0.05 ppm | 0.15 ppm | Skin |
| 75-52-5 | Nitromethane | 20 ppm | 30 ppm | |
| 108-03-2 | 1-Nitropropane | 25 ppm | 40 ppm | |
| 79-46-9 | 2-Nitropropane | 10 ppm | 20 ppm | T20 |
| 88-72-2; 99-08-1; 99-99-0 | Nitrotoluene isomers | 2 ppm | 3 ppm | Skin |
| 10024-97-2 | Nitrous oxide | 50 ppm | 75 ppm | |
| 111-84-2 | Nonane, all isomers | 200 ppm | 250 ppm | |
| 2234-13-1 | Octachloronaphthalene | 0.1 mg/m3 | 0.3 mg/m3 | Skin |
| 111-65-9 | Octane, all isomers | 300 ppm | 375 ppm | |
| 8012-95-1 | Oil mist, mineral | 5 mg/m3 | 10 mg/m3 | |
| 20816-12-0 | Osmium tetroxide, (as Os) | 0.0002 ppm | 0.0006 ppm | |
| 144-62-7 | Oxalic acid | 1 mg/m3 | 2 mg/m3 | |
| 80-51-3 | p,p'-Oxybis(benzenesulphonyl hydrazide), (inhalable fraction++) | 0.1 mg/m3 | 0.3 mg/m3 | |
| 7783-41-7 | Oxygen difluoride | **C0.05 ppm | ||
| 10028-15-6 | Ozone | 0.05 ppm | 0.15 ppm | |
| 8002-74-2 | Paraffin wax fume | 2 mg/m3 | 4 mg/m3 | |
| 4685-14-7 | Paraquat, total dust | 0.5 mg/m3 | 1.5 mg/m3 | |
| Paraquat, (respirable fraction++) | 0.1 mg/m3 | 0.3 mg/m3 | ||
| 56-38-2 | Parathion, (inhalable fraction++ and vapour) | 0.05 mg/m3 | 0.15 mg/m3 | Skin |
| ----- | Particulate polycyclic aromatic hydrocarbons (PPAH), as benzene solubles, See Coal tar pitch volatiles | 0.2 mg/m3 | 0.6 mg/m3 | T20 |
| ----- | Particles (Insoluble or Poorly Soluble) Not Otherwise Specified: | |||
| Inhalable fraction++ | 10 mg/m3 | 20 mg/m3 | ||
| Respirable fraction++ | 3 mg/m3 | 6 mg/m3 | ||
| 19624-22-7 | Pentaborane | 0.005 ppm | 0.015 ppm | |
| 1321-64-8 | Pentachloronaphthalene | 0.5 mg/m3 | 1.5 mg/m3 | Skin |
| 82-68-8 | Pentachloronitrobenzene | 0.5 mg/m3 | 1.5 mg/m3 | |
| 87-86-5 | Pentachlorophenol | 0.5 mg/m3 | 1.5 mg/m3 | Skin |
| 115-77-5 | Pentaerythritol | 10 mg/m3 | 20 mg/m3 | |
| 78-78-4; 109-66-0; 463-82-1 | Pentane, all isomers | 600 ppm | 750 ppm | |
Contamination Limits...cont'd
| CAS Number | Substance | 8 hour average contamination limit mg/m³* or ppm* | 15 minute average contamination limit mg/m³* or ppm* | Notation+ |
| 628-63-7; 626-38-0; 123-92-2; 625-16-1; 624-41-9; 620-11-1 | Pentyl acetate, all isomers | 50 ppm | 100 ppm | |
| 594-42-3 | Perchloromethyl mercaptan | 0.1 ppm | 0.3 ppm | |
| 7616-94-6 | Perchloryl fluoride | 3 ppm | 6 ppm | |
| 19430-93-4 | Perfluorobutyl ethylene | 100 ppm | 150 ppm | |
| 382-21-8 | Perfluoroisobutylene | **C0.01 ppm | ||
| 93763-70-3 | Perlite | 10 mg/m3 | 20 mg/m3 | |
| Persulphates, as persulphate | 0.1 mg/m3 | 0.3 mg/m3 | ||
| 108-95-2 | Phenol | 5 ppm | 7.5 ppm | Skin |
| 92-84-2 | Phenothiazine | 5 mg/m3 | 10 mg/m3 | Skin |
| 95-54-5; 108-45-2; 106-50-3 | Phenylene diamine isomers | 0.1 mg/m3 | 0.3 mg/m3 | |
| 101-84-8 | Phenyl ether (vapour) | 1 ppm | 2 ppm | |
| 122-60-1 | Phenyl glycidyl ether (PGE) | 0.1 ppm | 0.3 ppm | Skin, SEN, T20 |
| 100-63-0 | Phenyl hydrazine | 0.1 ppm | 0.3 ppm | Skin, T20 |
| 108-98-5 | Phenyl mercaptan | 0.1 ppm | 0.3 ppm | Skin |
| 638-21-1 | Phenylphosphine | **C0.05 ppm | ||
| 298-02-2 | Phorate (inhalable fraction++ and vapour) | 0.05 mg/m3 | 0.2 mg/m3 | Skin |
| 75-44-5 | Phosgene (Carbonyl chloride) | 0.1 ppm | 0.3 ppm | |
| 7803-51-2 | Phosphine | 0.3 ppm | 1 ppm | |
| 7664-38-2 | Phosphoric acid | 1 mg/m3 | 3 mg/m3 | |
| 12185-10-3 | Phosphorus (yellow) | 0.1 mg/m3 | 0.3 mg/m3 | |
| 10025-87-3 | Phosphorous oxychloride | 0.1 ppm | 0.3 ppm | |
| 10026-13-8 | Phosphorous pentachloride | 0.1 ppm | 0.3 ppm | |
| 1314-80-3 | Phosphorous pentasulphide | 1 mg/m3 | 3 mg/m3 | |
| 7719-12-2 | Phosphorous trichloride | 0.2 ppm | 0.5 ppm | |
| 85-44-9 | Phthalic anhydride | 1 ppm | 2 ppm | SEN |
| 626-17-5 | m-Phthalodinitrile | 5 mg/m3 | 10 mg/m3 | |
| 1918-02-1 | Picloram | 10 mg/m3 | 20 mg/m3 | |
| 88-89-1 | Picric acid | 0.1 mg/m3 | 0.3 mg/m3 | |
| 83-26-1 | Pindone | 0.1 mg/m3 | 0.3 mg/m3 | |
| 142-64-3 | Piperazine dihydrochloride | 5 mg/m3 | 10 mg/m3 | |
| 7778-18-9 | Plaster of Paris (Calcium sulphate) | 10 mg/m3 | 20 mg/m3 | |
| 7440-06-4 | Platinum: | |||
| metal | 1 mg/m3 | 3 mg/m3 | ||
| soluble salt, (as Pt) | 0.002 mg/m3 | 0.006 mg/m3 | ||
| 65997-15-1 | Portland cement | 10 mg/m3 | 20 mg/m3 | |
| 1310-58-3 | Potassium hydroxide | **C2 mg/m3 | ||
| 74-98-6 | Propane | See Aliphatic hydrocarbon gases [C1-C4] | ||
| 107-19-7 | Propargyl alcohol | 1 ppm | 3 ppm | Skin |
| 57-57-8 | beta-Propriolactone | 0.5 ppm | 1 ppm | T20 |
| 123-38-6 | Propionaldehyde | 20 ppm | 30 ppm | |
| 79-09-4 | Propionic acid | 10 ppm | 15 ppm | |
| 114-26-1 | Propoxur | 0.5 mg/m3 | 1.5 mg/m3 | |
| 109-60-4 | n-Propyl acetate | 200 ppm | 250 ppm | |
| 71-23-8 | Propyl alcohol (n-propanol) | 200 ppm | 400 ppm | |
| 78-87-5 | Propylene dichloride | 75 ppm | 110 ppm | |
| 6423-43-4 | Propylene glycol dinitrate | 0.05 ppm | 0.15 ppm | Skin |
| 107-98-2 | Propylene glycol monomethyl ether (PGME or 1-methoxy-2-propanol) | 100 ppm | 150 ppm | |
| 75-56-9 | Propylene oxide | 2 ppm | 4 ppm | SEN, T20 |
| 75-55-8 | Propylenimine | 2 ppm | 4 ppm | Skin, T20 |
| 627-13-4 | n-Propyl nitrate | 25 ppm | 40 ppm | |
| 8003-34-7 | Pyrethrum | 5 mg/m3 | 10 mg/m3 | |
| 110-86-1 | Pyridine | 1 ppm | 3 ppm | |
| 106-51-4 | Quinone | 0.1 ppm | 0.3 ppm | |
| 108-46-3 | Resorcinol | 10 ppm | 20 ppm | |
| 7440-16-6 | Rhodium, (as Rh): | |||
| Metal and insoluble compounds | 1 mg/m3 | 3 mg/m3 | ||
| Soluble compounds | 0.01 mg/m3 | 0.03 mg/m3 | ||
| 299-84-3 | Ronnel | 10 mg/m3 | 20 mg/m3 | |
| 83-79-4 | Rotenone (commercial) | 5 mg/m3 | 10 mg/m3 | |
| ----- | Rouge | 10 mg/m3 | 20 mg/m3 | |
| 8030-30-6 | Rubber solvent (Naphtha) | 400 ppm | 500 ppm | |
| 7782-49-2 | Selenium and compounds, (as Se) | 0.2 mg/m3 | 0.6 mg/m3 | |
| 7783-79-1 | Selenium hexafluoride, (as Se) | 0.05 ppm | 0.15 ppm | |
| 136-78-7 | Sesone | 10 mg/m3 | 20 mg/m3 | |
| Silica Amorphous: | ||||
| 61790-53-2 | Diatomaceous earth (uncalcined) (inhalable fraction ++) | 10 mg/m3 | 20 mg/m3 | |
| 61790-53-2 | Diatomaceous earth (uncalcined) (respirable fraction ++) | 3 mg/m3 | 6 mg/m3 | |
| 112926-00-8 | Precipitated silica and silica gel | 10 mg/m3 | 20 mg/m3 | |
| 69012-46-2 | Silica, fume (respirable fraction++) | 2 mg/m3 | ||
| 60676-86-0 | Silica, fused (respirable fraction++) | 0.1 mg/m3 | ||
| Silica - Crystalline#: | ||||
| 14464-46-1 | Cristobalite (respirable fraction++) | 0.05 mg/m3 | ||
| 14808-60-7 | Quartz (respirable fraction++) | 0.05 mg/m3 | T20 | |
| 1317-95-9 | Tripoli, as quartz (respirable fraction++) | 0.1 mg/m3 | ||
| 7440-21-3 | Silicon | 10 mg/m3 | 20 mg/m3 | |
| 409-21-2 | Silicon Carbide | |||
| Nonfibrous, (inhalable fraction++) | 10 mg/m3 | 20 mg/m3 | ||
| Nonfibrous, (respirable fraction++) | 3 mg/m3 | 6 mg/m3 | ||
| Fibrous (including whiskers), (respirable fibres) | 0.1 f/cc## | T20 | ||
| 7803-62-5 | Silicon tetrahydride (Silane) | 5 ppm | 10 ppm | |
| 7440-22-4 | Silver, metal | 0.1 mg/m3 | 0.3 mg/m3 | |
| ----- | Silver soluble compounds, (as Ag) | 0.01 mg/m3 | 0.03 mg/m3 | |
| ----- | Soapstone (total dust) | 6 mg/m3 | ||
| ----- | Soapstone (respirable fraction++) | 3 mg/m3 | 6 mg/m3 | |
| 26628-22-8 | Sodium azide: | |||
| as Sodium azide | **C0.29 mg/m3 | |||
| as Hydrazoic acid vapour | **C0.11 ppm | |||
| 7631-90-5 | Sodium bisulphite | 5 mg/m3 | 10 mg/m3 | |
| 62-74-8 | Sodium fluoroacetate | 0.05 mg/m3 | 0.15 mg/m3 | Skin |
| 1310-73-2 | Sodium hydroxide | **C2 mg/m3 | ||
| 7681-57-4 | Sodium metabisulphite | 5 mg/m3 | 10 mg/m3 | |
| 9005-25-8 | Starch | 10 mg/m3 | 20 mg/m3 | |
| ----- | Stearates | 10 mg/m3 | 20 mg/m3 | |
| 7803-52-3 | Stibine (Antimony hydride) | 0.1 ppm | 0.3 ppm | |
| 8052-41-3 | Stoddard solvent | 100 ppm | 125 ppm | |
| 7789-06-2 | Strontium chromate, (as Cr) | 0.0005 mg/m3 | 0.0015 mg/m3 | T20 |
| 57-24-9 | Strychnine | 0.15 mg/m3 | 0.45 mg/m3 | |
| 100-42-5 | Styrene, monomer | 20 ppm | 40 ppm | T20 |
| 1395-21-7; 9014-01-1 | Subtilisins, (as crystalline active enzyme) | **C0.00006 mg/m3 | ||
| 57-50-1 | Sucrose | 10 mg/m3 | 20 mg/m3 | |
| 74222-97-2 | Sulphometuron methyl | 5 mg/m3 | 10 mg/m3 | |
| 3689-24-5 | Sulphotep (TEDP) (inhalable fraction++ and vapour) | 0.1 mg/m3 | 0.3 mg/m3 | Skin |
| 7446-09-5 | Sulphur dioxide | 2 ppm | 5 ppm | |
| 2551-62-4 | Sulphur hexafluoride | 1000 ppm | 1250 ppm | |
| 7664-93-9 | Sulphuric acid, (thoracic fraction++) | 0.2 mg/m3 | 0.6 mg/m3 | T20, strong acid mists only |
| 10025-67-9 | Sulphur monochloride | **C1 ppm | ||
| 5714-22-7 | Sulphur pentafluoride | **C0.01 ppm | ||
| 7783-60-0 | Sulphur tetrafluoride | **C0.1 ppm | ||
| 2699-79-8 | Sulphuryl fluoride | 5 ppm | 10 ppm | |
| 35400-43-2 | Sulprofos | 1 mg/m3 | 3 mg/m3 | |
| Synthetic Vitreous Fibres: | ||||
| Continous filament glass fibres, (respirable fibres) | 1 f/cc## | 3 f/cc | ||
| Continous filament glass fibres, (inhalable fraction++) | 5 mg/m3 | 10 mg/m3 | ||
| Glass wool fibres, (respirable fibres) | 1 f/cc | 3 f/cc | ||
| Rock wool fibres, (respirable fibres) | 1 f/cc | 3 f/cc | ||
| Slag wool fibres, (respirable fibres) | 1 f/cc | 3 f/cc | ||
| Special purpose glass fibres, (respirable fibres) | 1 f/cc | 3 f/cc | ||
| Refractory ceramic fibres, (respirable fibres) | 0.2 f/cc | T20 | ||
| 93-76-5 | 2,4,5-T | 10 mg/m3 | 20 mg/m3 | |
| 14807-96-6 | Talc, (respirable fraction++) | 2 mg/m3 | ||
| 7440-25-7 | Tantalum metal and oxide, (as Ta) | 5 mg/m3 | 10 mg/m3 | |
| 7783-80-4 | Tellurium hexafluoride, (as Te) | 0.02 ppm | 0.03 ppm | |
| 13494-80-9 | Tellurium and other tellurium compounds, (as Te) excluding hydrogen telluride | 0.1 mg/m3 | 0.3 mg/m3 | |
| 3383-96-8 | Temephos, (inhalable fraction++ and vapour) | 1 mg/m3 | 3 mg/m3 | Skin |
| 13071-79-9 | Terbufos, (inhalable fraction++ and vapour) | 0.01 mg/m3 | 0.03 mg/m3 | Skin |
| 100-21-0 | Terephthalic acid | 10 mg/m3 | 20 mg/m3 | |
| 26140-60-3 | Terphenyls | **C5 mg/m3 | ||
| 76-11-9 | 1,1,1,2-Tetrachloro-2, 2-difluoroethane | 500 ppm | 625 ppm | |
| 76-12-0 | 1,1,2,2-Tetrachloro-1, 2-difluoroethane | 500 ppm | 625 ppm | |
| 79-34-5 | 1,1,2,2-Tetrachloroethane | 1 ppm | 2 ppm | Skin |
| 127-18-4 | Tetrachloroethylene (Perchloroethylene) | 25 ppm | 100 ppm | T20 |
| 1335-88-2 | Tetrachloronaphthalene | 2 mg/m3 | 4 mg/m3 | |
| 78-00-2 | Tetraethyl lead, (as Pb) | 0.1 mg/m3 | 0.3 mg/m3 | Skin |
| 107-49-3 | Tetraethyl pyrophosphate (TEPP) | 0.05 mg/m3 | 0.15 mg/m3 | Skin |
| 116-14-3 | Tetrafluoroethylene | 2 ppm | 4 ppm | T20 |
Contamination Limits...cont'd
| CAS Number | Substance | 8 hour average contamination limit mg/m³* or ppm* | 15 minute average contamination limit mg/m³* or ppm* | Notation+ |
| 109-99-9 | Tetrahydrofuran | 50 ppm | 100 ppm | Skin |
| Tetrakis (hydroxymethyl) phosphonium salts: | ||||
| 124-64-1 | Tetrakis (hydroxymethyl) phosphonium chloride | 2 mg/m3 | 4 mg/m3 | |
| 55566-30-8 | Tetrakis (hydroxymethyl) phosphonium sulphate | 2 mg/m3 | 4 mg/m3 | SEN |
| 75-74-1 | Tetramethyl lead, (as Pb) | 0.15 mg/m3 | 0.45 mg/m3 | Skin |
| 3333-52-6 | Tetramethyl succinonitrile | 0.5 ppm | 1 ppm | Skin |
| 509-14-8 | Tetranitromethane | 0.005 ppm | 0.015 ppm | T20 |
| 7722-88-5 | Tetrasodium pyrophosphate | 5 mg/m3 | 10 mg/m3 | |
| 479-45-8 | Tetryl (2,4,6-trinitrophenyl-methyl nitramine) | 1.5 mg/m3 | 3 mg/m3 | |
| 7440-28-0 | Thallium and soluble compounds, (as Tl) | 0.1 mg/m3 | 0.3 mg/m3 | Skin |
| 96-69-5 | 4,4'-Thiobis (6-tert-butyl-m-cresol) | 10 mg/m3 | 20 mg/m3 | |
| 68-11-1 | Thioglycolic acid | 1 ppm | 2 ppm | Skin |
| 7719-09-7 | Thionyl chloride | **C1 ppm | ||
| 137-26-8 | Thiram | 1 mg/m3 | 3 mg/m3 | |
| 7440-31-5 | Tin, (as Sn): | |||
| metal | 2 mg/m3 | 4 mg/m3 | ||
| oxide and inorganic compounds except SnH4 | 2 mg/m3 | 4 mg/m3 | ||
| organic compounds | 0.1 mg/m3 | 0.2 mg/m3 | Skin | |
| 13463-67-7 | Titanium dioxide | 10 mg/m3 | 20 mg/m3 | |
| 108-88-3 | Toluene (toluol) | 50 ppm | 60 ppm | Skin |
| 584-84-9; 91-08-7 | Toluene-2,4- or 2,6-diisocyanate (TDI) | 0.005 ppm | 0.02 ppm | SEN |
| 95-53-4 | o-Toluidine | 2 ppm | 4 ppm | Skin, T20 |
| 108-44-1 | m-Toluidine | 2 ppm | 4 ppm | Skin |
| 106-49-0 | p-Toluidine | 2 ppm | 4 ppm | Skin, T20 |
| 126-73-8 | Tributyl phosphate | 0.2 ppm | 0.4 ppm | |
| 76-03-9 | Trichloroacetic acid | 1 ppm | 2 ppm | |
| 120-82-1 | 1,2,4-Trichlorobenzene | **C5 ppm | ||
| 71-55-6 | 1,1,1-Trichloroethane | 350 ppm | 450 ppm | |
| 79-00-5 | 1,1,2-Trichloroethane | 10 ppm | 15 ppm | Skin |
| 79-01-6 | Trichloroethylene | 50 ppm | 100 ppm | |
| 75-69-4 | Trichlorofluoromethane | **C1000 ppm | ||
| 1321-65-9 | Trichloronaphthalene | 5 mg/m3 | 10 mg/m3 | Skin |
| 96-18-4 | 1,2,3-Trichloropropane | 10 ppm | 15 ppm | Skin |
| 76-13-1 | 1,1,2-Trichloro-1,2,2-trifluoroethane | 1000 ppm | 1250 ppm | |
| 52-68-6 | Trichlorphon, (inhalable fraction++) | 1 mg/m3 | 3 mg/m3 | |
| 102-71-6 | Triethanolamine | 5 mg/m3 | 10 mg/m3 | |
| 121-44-8 | Triethylamine | 1 ppm | 3 ppm | Skin |
| 75-63-8 | Trifluorobromomethane | 1000 ppm | 1200 ppm | |
| 2451-62-9 | 1,3,5-Triglycidyl-s-triazinetrione | 0.05 mg/m3 | 0.15 mg/m3 | |
| 552-30-7 | Trimellitic anhydride | **C0.04 mg/m3 | ||
| 75-50-3 | Trimethylamine | 5 ppm | 15 ppm | |
| 25551-13-7 | Trimethyl benzene (mixed isomer) | 25 ppm | 30 ppm | |
| 121-45-9 | Trimethyl phosphite | 2 ppm | 4 ppm | |
| 118-96-7 | 2,4,6-Trinitrotoluene (TNT) | 0.1 mg/m3 | 0.3 mg/m3 | Skin |
| 78-30-8 | Triorthocresyl phosphate | 0.1 mg/m3 | 0.3 mg/m3 | Skin |
| 603-34-9 | Triphenylamine | 5 mg/m3 | 10 mg/m3 | |
| 115-86-6 | Triphenyl phosphate | 3 mg/m3 | 6 mg/m3 | |
| 7440-33-7 | Tungsten, (as W): | |||
| metal and insoluble compounds | 5 mg/m3 | 10 mg/m3 | ||
| soluble compounds | 1 mg/m3 | 3 mg/m3 | ||
| 8006-64-2; 80-56-8; 127-91-3; 13466-78-9 | Turpentine and selected monoterpenes | 20 ppm | 30 ppm | SEN |
| 7440-61-1 | Uranium (natural) | |||
| Soluble and insoluble compounds, (as U) | 0.2 mg/m3 | 0.6 mg/m3 | T20 | |
| 110-62-3 | n-Valeraldehyde | 50 ppm | 60 ppm | |
| 1314-62-1 | Vanadium pentoxide, as V2O5, dust and fume (respirable fraction++) | 0.05 mg/m3 | 0.15 mg/m3 | |
| ----- | Vegetable oil mists | 10 mg/m3 | 20 mg/m3 | |
| 108-05-4 | Vinyl acetate | 10 ppm | 15 ppm | |
| 593-60-2 | Vinyl bromide | 0.5 ppm | 1.5 ppm | T20 |
| 100-40-3 | 4-Vinyl cyclohexene | 0.1 ppm | 0.3 ppm | T20 |
| 106-87-6 | Vinyl cyclohexene dioxide | 0.1 ppm | 0.3 ppm | Skin, T20 |
| 75-02-5 | Vinyl fluoride | 1 ppm | 3 ppm | T20 |
| 88-12-0 | N-Vinyl-2-pyrrolidone | 0.05 ppm | 0.15 ppm | |
| 75-35-4 | Vinylidene chloride | 5 ppm | 10 ppm | |
| 75-38-7 | Vinyledene fluoride | 500 ppm | 625 ppm | |
| 25013-15-4 | Vinyl toluene | 50 ppm | 100 ppm | |
| 8032-32-4 | VM and P Naphtha | 300 ppm | 375 ppm | |
| 81-81-2 | Warfarin | 0.1 mg/m3 | 0.3 mg/m3 | |
| ----- | Welding fumes | 5 mg/m3 | 10 mg/m3 | |
| Wood dust: | ||||
| ----- | Softwoods | 5 mg/m3 | 10 mg/m3 | T20 (certain species), SEN* (certain species, see list at end of table) |
| ----- | Certain hardwoods such as beech and oak | 1 mg/m3 | 3 mg/m3 | T20 (certain species), SEN* (certain species, see list at end of table) |
| 1330-20-7; 95-47-6; 108-38-3; 106-42-3 | Xylene (o, m-, p-isomers) | 100 ppm | 150 ppm | |
| 1477-55-0 | m-Xylene alpha, alpha'-diamine | **C0.1 mg/m3 | Skin | |
| 1300-73-8 | Xylidine, mixed isomers (inhalable fraction++ and vapour) | 0.5 ppm | 1 ppm | T20, Skin |
| 7440-65-5 | Yttrium metal and compounds, (as Y) | 1 mg/m3 | 3 mg/m3 | |
| 7646-85-7 | Zinc chloride fume | 1 mg/m3 | 2 mg/m3 | |
| 13530-65-9; 11103-86-9; 37300-23-5 | Zinc chromates, as Cr | 0.01 mg/m3 | 0.03 mg/m3 | T20 |
| 1314-13-2 | Zinc oxide, fume and dust (respirable fraction++) | 2 mg/m3 | 10 mg/m3 | |
| 7440-67-7 | Zirconium and compounds, (as Zr) | 5 mg/m3 | 10 mg/m3 | |
*mg/m3 - milligrams of substance per cubic metre of air; ppm - parts (volume) of substance per million parts (volume) of air
**C - ceiling limit.
Notes:
# - Trydimite removed
## - Fibres per cubic centimeter of air
+ - Explanation of Notations:
T20 - Substance is also In Table 20 and subject to Sections 306 and 311
Skin - Potentially harmful after absorption through the skin or mucous membranes
SEN - Well-demonstrated potential to produce sensitization
SEN* - Wood species suspected of inducing sensitization (see Table D)
Inhalable fraction:
For the application of this limit, inhalable fraction is that fraction of the aerosol that passes a size selector with the following characteristics:
Table A
| Particle Aerodynamic Diameter (µm) | Inhalable Particulate Mass (IPM) (%) |
| 100 | |
| 1 | 97 |
| 2 | 94 |
| 5 | 87 |
| 10 | 77 |
| 20 | 65 |
| 30 | 58 |
| 40 | 54.5 |
| 50 | 52.5 |
| 100 | 50 |
Respirable fraction:
For the application of this limit, respirable fraction is that fraction of the aerosol that passes a size selector with the following characteristics:
Table B
| Particle Aerodynamic Diameter (µm) | Respirable Particulate Mass (RPM) (%) |
| 0 | 100 |
| 1 | 97 |
| 2 | 91 |
| 3 | 74 |
| 4 | 50 |
| 5 | 30 |
| 6 | 17 |
| 7 | 9 |
| 8 | 5 |
| 10 | 1 |
Thoracic fraction:
For the application of this limit, thoracic fraction is that fraction of the aerosol that passes a size selector with the following characteristics:
Particle Aerodynamic Diameter ( m) Particulate Mass
Table C
| Particle Aerodynamic Diameter (µm) | Thoracic Particulate Mass (TPM) (%) |
| 0 | 100 |
| 2 | 94 |
| 4 | 89 |
| 6 | 80.5 |
| 8 | 67 |
| 10 | 50 |
| 12 | 35 |
| 14 | 23 |
| 16 | 15 |
| 18 | 9.5 |
| 20 | 6 |
| 25 | 2 |
Commercially Important Tree Species Suspected of Inducing Sensitization
Table D
| Common | Latin |
| SOFTWOODS | |
| California redwood | Sequoia sempervirens |
| Eastern white cedar | Thuja occidentalis |
| Pine | Pinus |
| Western red cedar | Thuja plicata |
| HARDWOOD | |
| Ash | Fraxinus americana |
| Aspen/Poplar/Cottonwood | Popilus |
| Beech | Fagus |
| Oak | Quercus |
| TROPICAL WOODS | |
| Abirucana | Pouteria |
| African zebra | Microberlinia |
| Antiaris | Antiaris africana Antiaris toxicara |
| Cabreuva | Myrocarpus fastigiatus |
| Cedar of Lebanon | Cedra libani |
| Central American walnut | Juglans olanchana |
| Cocabolla | Dalbergia retusa |
| African ebony | Diospryos crassiflora |
| Fernam bouc | Caesalpinia |
| Honduras rosewood | Dalbergia stevensonii |
| Iroko or kambala | Chlorophora excelsa |
| Kejaat | Pterocarpus angolensis |
| Kotobe | Nesorgordonia papaverifera |
| Limba | Terminalia superba |
| Mahogany (African) | Khaya spp. |
| Makore | Tieghemella heckelii |
| Mansonia/Beté | Mansonia altissima |
| Nara | Pterocarpus indicus |
| Obeche/African maple/Samba | Triplochiton scleroxylon |
| Palisander/Brazilian rosewood/ Tulip wood/Jakaranda | Dalbergia nigra |
| Pau marfim | Balfourdendron riedelianum |
| Ramin | Gonystylus bancanus |
| Soapbark dust | Quillaja saponaria |
| Spindle tree wood | Euonymus europaeus |
| Tanganyike aningre |
[Sask. Reg. 6/97, s. 14; 67/2007, s. 33]
Mines Regulations, 2003
R.R.S., c. O-1, r. 2
Part XIV Air Quality and Ventilation Underground at a Mine
Section 292 Airborne contaminants
292. (1) In this section, "uncombined silica" means silica that is not combined chemically with any other element or compound.
(2) An employer or contractor must take all reasonably practicable steps to minimize the dissemination of dust into any active mining area underground at a mine.
(3) Except as otherwise provided in these regulations, to the extent that is reasonably practicable, an employer or contractor must ensure that in any underground part of a mine where workers work or pass:
(a) the concentration of airborne carbon monoxide does not exceed 25 parts per million at any time;
(b) the concentration of airborne carbon dioxide does not exceed 5 000 parts per million at any time;
(c) the concentration of airborne nitrogen dioxide does not exceed two parts per million at any time; and
(d) the oxygen content is not less than 19.5% and not more than 23%, by volume at any time.
(4) If mining is carried out underground in strata containing uncombined silica in a crystalline form, an employer or contractor must:
(a) so far as is reasonably practicable, minimize the dissemination of dust into the general mine air during the construction, use and maintenance of every ore pass;
(b) provide an effective means to spray water within a suitable distance of the working face of every drift or raise to suppress any dust;
(c) ensure that the spray mentioned in clause (b) is used for a minimum of 15 minutes after any blasting operation is complete; and
(d) provide every drill with a water jet, spray or other suitable attachment to prevent dust from escaping and ensure that the attachment is used at all times during a drilling operation.