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Good air quality in construction is an important component of a healthy and safe working environment. Air quality concerns may be caused by improper or inadequately maintained heating and ventilation systems that affect temperature, humidity, and air circulation. Contaminants in the air from construction materials, glues, fibreglass, particle boards, paints, and chemicals can affect air quality and cause short-term and long-term health effects in workers.

Controls for air quality are most effective when they are selected according to the “hierarchy of control”. Proper ventilation helps to maintain good air quality and is used to:

  • Provide a continuous supply of fresh outside air;
  • Maintain temperature and humidity at comfortable levels;
  • Reduce potential fire or explosion hazards;
  • Remove or dilute contaminants such as fumes, dusts, and vapours

Ventilation can be accomplished by natural means (e.g., opening a window) or mechanical Industrial systems are designed to move out (exhaust) and bring in (intake) a specific amount of air at a specific speed (velocity), which results in the removal of undesirable contaminants. While all ventilation systems follow the same basic principles, each system is designed specifically to match to the type of work and the rate of contaminant release at that workplace.

Note: Requirements marked with * are also valid for owners.  Requirements marked with ** are valid for employers only. 

An employer or contractor must:

  • Ensure appropriate PPE is used and maintained;
  • Ensure the worker is provided with and uses approved atmosphere-supplying respirator when entering an atmosphere that is Immediately Dangerous to Life or Health (IDLH) of the worker;  
  • Ensure that all practicable emergency arrangements are made and measures are taken where  a worker is at risk of asphyxiation or poisoning;  
  • Ensure adequate ventilation of a place of employment*;  
  • Ensure the air is harmless and inoffensive;  
  • Ensure that a mechanical ventilation system is in a place of employment:*
    • Where any work, activity or process generates contaminants refer to leg. Sec 66; 
  • Ensure the mechanical ventilation system, including any humidification equipment, is constructed and maintained;  
  • Ensure that a smoking policy is in place as per section 77 in the OHS Regulations;  
  • Ensure a competent person fulfills the appropriate duties before a worker is required or permitted to enter a confined space;
  • Ensure that standards for air meet the following specifications:
    • Air supplied by a compressor plant; refer to section 280 in the OHS Regulations.  
    • Where air is used as the breathing gas; refer to section 291 in the OHS Regulations.**
    • Ensure that every asbestos process follows appropriate procedures;
    •  When silica releasing process is underway; refer to sections 346-358 in the OHS Regulations.  

Additional Duties for employers and contractors involved in mining:

Refer to The Mines Regulation, 2003

A worker must:

  • Stop any work or activity that may ignite gas if they detect or suspect flammable gas underground;  
  • Immediately notify the employer or contractor if they detect or suspect flammable gas underground;  

Occupational Health and Safety Regulations, 1996
S.S., c. O-1.1, Reg 1

Part XIX Work in Compressed Air

Section 280 Standards for air

280. An employer or contractor shall ensure that:

(a) the air supplied by a compressor plant for use in a working chamber, air lock or medical lock meets the requirements of the Canadian Standards Association standard CAN3-Z180.1-M85 Compressed Breathing Air and Systems;

(b) the air intake for a compressor plant that supplies air to a working chamber, an air lock or a medical lock is located so as to prevent the entry of exhaust gases from internal combustion engines, gasoline fumes or other contaminants; and

(c) the air supplied to a working chamber, air lock or medical lock is kept, as far as is practicable, between 10 and 27 Celsius.

Part XX Diving Operations

Section 291 Breathing gas

291. (1) Subject to subsection (2), where air is used as the breathing gas, an employer shall ensure that:

(a) the air is clean and wholesome and supplied in adequate quantity; and

(b) a reserve supply of 2.5 times the air required for the operation is supplied.

(2) An employer shall ensure that any air or mixed gas used as the breathing gas meets the approved standard for composition and purity requirements.

(3) Where a mixed gas is used as the breathing gas, an employer shall ensure that the decompression procedures, schedules and tables used are appropriate for the mixed gas.

Part XXIV Silica Processes and Abrasive Blasting

Section 346 Interpretation

346. In this Part:

(a) "abrasive blasting" means the cleaning, smoothing, roughening or removing of part of the surface of any article by the use of a jet of sand, metal shot, grit or other material;

(b) "blasting enclosure" means a chamber, barrel, cabinet or other similar enclosure designed for the purpose of the abrasive blasting of articles;

(c) "cleaning of castings" means, in connection with the making of metal castings, the freeing of the castings from adherent sand or other substance containing more than 5% uncombined silica, and includes the removal of cores and the general smoothing of the castings where that freeing is done, but does not include the freeing of castings from scale formed during annealing or heat treatment;

(d) "sandblasting" means an abrasive blasting process that uses sand as an abrasive;

(e) "silica flour" means the ground material produced by the milling of siliceous rocks or other siliceous substances;

(f) "silica process" means a process that may release uncombined silica in a crystalline form in concentrations likely to exceed the contamination limits set out in Table 21 of the Appendix, and includes:

(i) sandblasting;

(ii) the cleaning of castings;

(iii) the abrasive blasting, grinding or dressing of any surface that contains more than 5% uncombined silica, including the engraving or abrasive cleaning of gravestones or structures;

(iv) the getting, cutting, splitting, crushing, grinding, milling, drilling, sieving or other mechanical manipulation of gravel or other siliceous stone or rock that contains more than 5% uncombined silica;

(v) any process in which silica flour is used; and

(vi) the manufacture of silica-containing bricks and the dismantling or repair of silica-containing refractory linings of furnaces;

(g) "siliceous substances" includes diatomite;

(h) "uncombined silica" means silica that is not combined chemically with any other element or compound.

Section 347 Application of Part

347. This Part applies to any place of employment or worksite where a silica process is used.

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 V First Aid

Section 62 Asphyxiation and poisoning

62. Where a worker is at risk of asphyxiation or poisoning, an employer or contractor shall ensure that all practicable emergency arrangements are made for the rescue of the worker and for the prompt provision of antidotes, supportive measures, first aid, medical attention and any other measures that are appropriate to the nature and probable effects of the asphyxia or poisoning.

Part VI General Health Requirements

Section 65 Ventilation and air supply

65. An employer, contractor or owner shall:

(a) ensure the adequate ventilation of a place of employment; and

(b) to the extent that is reasonably practicable, render harmless and inoffensive, and prevent the accumulation of, any contaminants or impurities in the air by providing an adequate supply of clean and wholesome air and maintaining its circulation throughout the place of employment.

Section 66 Mechanical ventilation

66. (1) An employer, contractor or owner shall provide a mechanical ventilation system in a place of employment that is sufficient and suitable to protect the workers against inhalation of a contaminant and to prevent accumulation of the contaminant and ensure that the mechanical ventilation system is maintained and properly used, where any work, activity or process in the place of employment gives off:

(a) a dust, fume, gas, mist, aerosol or vapour or other contaminant of a kind and quantity that is likely to be hazardous to workers; or

(b) substantial quantities of contaminants of any kind.

(2) An employer, contractor or owner who provides a mechanical ventilation system at a place of employment, whether required by subsection (1) or not, shall ensure that the system provides sufficient fresh and tempered air to replace the air exhausted by ventilation.

(3) Where practicable, an employer, contractor or owner shall ensure that a mechanical ventilation system required by subsection (1):

(a) includes local exhaust ventilation that is installed and maintained at or near the point of origin of the contaminant so as to prevent effectively the contaminant from entering the air of the place of employment; and

(b) is equipped with a device that will provide a warning to workers when the system is not working effectively.

(4) An employer, contractor or owner shall ensure that contaminants removed by a mechanical ventilation system required by subsection (1) are:

(a) exhausted clear of the place of employment; and

(b) where reasonably practicable, prevented from entering any place of employment.

(5) An employer, contractor or owner shall ensure that effective provision is made for the immediate protection of workers in the event of failure of a mechanical ventilation system required by subsection (1).

(6) Where an air cleaning system is used to clean recirculated air, an employer, contractor or owner shall ensure that the air cleaning system is designed, installed and maintained to remove particulate and gaseous contaminants at a rate that is sufficient to protect the health and safety of workers and, where reasonably practicable, to render the air inoffensive.

Section 67 Cleaning and maintaining ventilation systems

67. (1) An employer, contractor or owner shall ensure that:

(a) the mechanical ventilation system, including any humidification equipment, is constructed and maintained to minimize the growth and dissemination of micro-organisms, insects and mites through the ventilation system; and

(b) where reasonably practicable, the components of a mechanical ventilation system are readily accessible for cleaning and inspection.

(2) An employer, contractor or owner shall ensure that a competent person inspects and maintains all parts of a mechanical ventilation system, cleans all louvres and replaces or adequately cleans all filters at a frequency that is sufficient to protect the health and safety of the workers.

(3) An employer, contractor or owner shall keep all ventilation openings free of any obstruction or source of contamination.

(4) An employer, contractor or owner shall ensure that a record of all inspections, maintenance and cleaning of a mechanical ventilation system required by subsection 66(1):

(a) is made by the competent person who performs the work; and

(b) is readily available for examination by the committee, the representative or, where there is no committee or representative, the workers.

Section 77 Smoking

77. (1) In this section:

(a)"enclosed place of employment" means a place of employment that is within a building or another enclosed place and includes:

(i) a vehicle; and

(ii) any of the following areas of an underground mine:

(A) a mine shaft;

(B) a refuge station required pursuant to The Mines Regulations, 2003 ;

(C) a lunch room;

(D) any area, other than one mentioned in paragraphs (A) to (C), that is within 10 metres of where a worker, self-employed person, employer, contractor or owner is present;

(b) "enclosed work-related area" means a work-related area that is within a building or another enclosed place;

(c) "enclosed worksite" means a worksite that is within a building or another enclosed place;

(d) "smoke" means to smoke, hold or otherwise have control over ignited tobacco;

(e) "tobacco" means tobacco in any form in which it is used or consumed, and includes snuff and raw leaf tobacco, but does not include any food, drug or device that contains nicotine to which the Food and Drugs Act (Canada) applies.

(2) Subject to subsections (3) and (4), an employer, contractor or owner shall ensure that no person smokes in:

(a) an enclosed place of employment;

(b) an enclosed work-related area; or

(c) any other place of employment where smoking is prohibited by law.

(3) Subsection (2) does not apply to the following places or persons:

(a) an enclosed place of employment or enclosed work-related area while it is being used with the consent of the proprietor for traditional Aboriginal spiritual or cultural practices or ceremonies, if the use of tobacco is an integral part of the traditional Aboriginal spiritual or cultural practices or ceremonies being carried out in the enclosed place of employment or enclosed workrelated area;

(b) residents or persons visiting residents in an enclosed place that:

(i) is ventilated separately from the rest of the enclosed place of employment or enclosed work-related area;

(ii) is within:

(A) a facility designated as a special-care home pursuant to The Regional Health Services Act; or

(B) a personal care home as defined in The Personal Care Homes Act that offers care and accommodation to more than 10 persons; and

(iii) meets the requirements prescribed in The Tobacco Control Act and the regulations made pursuant to that Act.

(4) No person while at work shall smoke in any enclosed place of employment or enclosed work-related area where smoking is prohibited pursuant to this section unless:

(a) the person is:

(i) a self-employed person in a place of employment that:

(A) is ventilated separately from other places of employment or work-related areas; and

(B) is owned by the self-employed person;

(ii) a worker in a vehicle who has the permission of the owner or lessee of the vehicle to smoke in the vehicle; or

(iii) a self-employed person or worker who is the sole occupant of a work camp living accommodation if:

(A) the living accommodation is ventilated separately from other places of employment or enclosed work-related areas; and

(B) the self-employed person or worker has the permission of the owner or operator of the work camp to smoke in the living accommodation;

(b) no other worker, self-employed person, employer, contractor or owner is present on a frequent and regular basis in any of the places of employment or enclosed work-related areas mentioned in clause (a); and

(c) no other worker, self-employed person, employer, contractor or owner is present when the person mentioned in clause (a) is smoking.

(5) Subject to subsection (6), a worker may refuse to enter an enclosed worksite if:

(a) visible tobacco smoke is present; or

(b) fewer than 30 minutes have passed since a tobacco product was extinguished in the enclosed worksite, whether or not visible tobacco smoke is present.

(6) Subsection (5) does not apply where the worker is required to enter the enclosed worksite to prevent imminent injury or damage to persons or property located within the enclosed worksite.

(7) If smoking is permitted pursuant to subsection (3) or (4), an employer, contractor or owner shall:

(a) restrict workers' exposure or self-employed persons' exposure to second-hand tobacco smoke to the extent that is reasonably practicable; and

(b) inform workers and self-employed persons of the risk to their health from second-hand tobacco smoke.

(8) An employer, contractor or owner shall ensure that in every enclosed place of employment where smoking is prohibited:

(a) signs are posted in locations that are clearly visible to those entering the enclosed place of employment that indicate that smoking is prohibited; and

(b) no ashtray or other receptacle designed to be used as an ashtray is present within the enclosed place of employment.

[Sask. Reg. 109/2008, s. 2]

Part VII Personal Protective Equipment

Section 90 Working in dangerous atmospheres

90. (1) Where a worker is required to enter an atmosphere that is immediately dangerous to the life or health of the worker, an employer or contractor shall ensure that the worker is provided with and uses an approved atmosphere-supplying respirator that is:

(a) an open-circuit SCBA that:

(i) operates in a pressure demand or other positive pressure mode;

(ii) has a minimum rated capacity of 30 minutes;

(iii) is sufficiently charged to enable the worker to perform the work safely; and

(iv) is equipped with a low-pressure warning device or an escape respirator;

(b) an airline respirator equipped with a full facepiece that:

(i) operates in a pressure demand or other positive pressure mode; and

(ii) has an auxiliary supply of air sufficient to allow the worker to escape in case of failure of the primary air supply equipment; or

(c) a closed-circuit SCBA.

(2) Where a worker is required to enter an atmosphere that is immediately dangerous to life or health, an employer or contractor shall ensure that:

(a) a second worker, suitably equipped and trained, is present and in communication with the worker at all times; and

(b) suitably equipped personnel who are trained in rescue procedures and are fully informed of the hazards are readily available to rescue the endangered worker immediately if the worker's atmosphere-supplying respirator fails or the worker becomes incapacitated for any other reason.

(3) An employer or contractor shall ensure that compressed air in an atmosphere-supplying respirator used by a worker in an atmosphere that is immediately dangerous to the worker's life or health meets the purity requirements set out in Table 2 of the Canadian Standards Association standard CAN3-Z180.1-M85 Compressed Breathing Air and Systems.

Mines Regulations, 2003
R.R.S., c. O-1, r. 2

Part XIV Air Quality and Ventilation Underground at a Mine

Section 291 Air quality underground

291. (1) An employer or contractor must develop and implement a written program to monitor the quality and quantity of the air in all parts of an underground mine except in those areas barricaded or fenced off.

(2) The air quality program mentioned in subsection (1) must:

(a) be developed in consultation with the committee; and

(b) contain a description of:

(i) the locations to be monitored;

(ii) the frequency at which the locations are to be monitored; and

(iii) the type of equipment to be used and how the equipment is to be calibrated.

(3) An employer or contractor must ensure that:

(a) a competent person is responsible for measuring the air quality at the mine;

(b) the person mentioned in clause (a) records the result of each measurement; and

(c) the records of the air quality program are readily available to workers.

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.

Section 293 Flammable gas underground

293. (1) A worker who detects or suspects flammable gas underground must:

(a) cease any work or activity that may ignite the gas; and

(b) immediately notify the employer or contractor.

(2) If flammable gas is detected in a dangerous concentration underground, an employer or contractor must:

(a) take immediate steps to protect the health and safety of any worker who may be at risk;

(b) designate the area as a fire hazard in accordance with section 352;

(c) identify the source of the gas; and

(d) control the hazard.

Section 294 General requirement for underground ventilation

294. (1) Sections 65 to 67 of the OHS regulations do not apply underground.

(2) Subject to subsection (3), an employer, contractor or owner must, in every underground mine:

(a) ensure adequate ventilation;

(b) provide a mechanical ventilation system that is suitable and adequate to protect workers against inhalation of a contaminant of a kind and quantity that is likely to be hazardous to workers;

(c) ensure that the mechanical ventilation system required by clause (b) is maintained and properly used; and

(d) if reasonably practicable, ensure that the mechanical ventilation system required by clause (b) is equipped with a device that will provide an audible or visual warning when the system is not working effectively.

(3) Any area in an underground mine that is barricaded or fenced off is not required to be ventilated.

Section 295 Failure of mechanical ventilation

295. (1) In this section, "stop", with respect to a mechanical ventilation system, does not include a stop that is caused by a brief interruption of the power supply.

(2) Subject to subsection (3), if the mechanical ventilation system underground at a mine fails or stops, the employer or contractor must ensure:

(a) that all persons are withdrawn from the affected area; and

(b) that no worker enters the affected area until:

(i) the mechanical ventilation system has been restored;

(ii) the affected area has been inspected by a competent person authorized by the employer or contractor; and

(iii) the employer or contractor determines that the affected area is safe and that work may proceed.

(3) If a mechanical ventilation system underground fails or stops or if its effect is reduced to the extent that worker health or safety may be affected, and if the employer or contractor determines that no immediate danger exists, work may continue if the employer or contractor ensures that:

(a) any activity that produces harmful contaminants underground is curtailed; and

(b) the quality of the air is monitored to ensure worker health and safety.

Section 296 Maintenance on mechanical ventilation system

296. An employer or contractor must ensure that adequate provision is made to provide suitable and adequate protection to workers conducting maintenance on a mechanical ventilation system underground while the mechanical ventilation system is stopped for maintenance.

Section 297 Ventilation near workings

297. An employer or contractor must ensure that:

(a) each underground working face is adequately ventilated; and

(b) if ventilation to an underground working face is provided by an auxiliary fan and ducts, the end of the duct is within 38 metres of the working face.

Section 298 Non-ventilated areas

298. (1) An employer or contractor must ensure that every entrance to a non-ventilated area is barricaded and a sign posted that:

(a) is placed in a conspicuous location;

(b) is legible;

(c) prohibits unauthorized entry; and

(d) if possible, identifies any specific hazard.

(2) An employer or contractor shall not permit a worker to enter or work in a non-ventilated area unless the employer or contractor has ensured that the non-ventilated area has been inspected and tested by a competent person who determines that:

(a) the air quality meets the standards described in subsection 292(3); and

(b) there is no other hazard.