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Appendix 2 - Respirator Requirements & Other Measures and Procedures for Type 1, 2, and 3 Silica-Containing Operations

  • Issued: September 2004
  • Content last reviewed: April 2011

Disclaimer: This resource has been prepared to help the workplace parties understand some of their obligations under the Occupational Health and Safety Act (OHSA) and regulations. It is not legal advice. It is not intended to replace the OHSA or the regulations. For further information please see full disclaimer.

Type Operations Required Respirator Other Measures & Procedures
Type 1
  • The drilling of holes in concrete or rock that is not part of a tunnelling operation or road construction.
  • Milling of asphalt from concrete highway pavement.
  • Charging mixers and hoppers with silica sand (sand consisting of at least 95 per cent silica) or silica flour (finely ground sand consisting of at least 95 per cent silica).
  • Any other operation at a project that requires the handling of silica-containing material in a way that may result in a worker being exposed to airborne silica.
  • Entry into a dry mortar removal or abrasive blasting area while airborne dust is visible for less than 15 minutes for inspection and/or sampling.
  • Working within 25 metres of an area where compressed air is being used to remove silica-containing dust outdoors.
Half-mask particulate respirator with N-, R-, or P-series filter and 95, 99 or 100% efficiency.
  • Clean-up after each operation should be done to prevent dust containing silica from spreading
  • Compressed air or dry sweeping should be avoided when cleaning a work area
  • Compressed air should not be used for removing dust from clothing
  • Workers exposed to silica should be provided with or have access to washing facilities equipped with clean water, soap, and individual towels
  • Silica dust on personal protective clothing and equipment should be removed by damp wiping or HEPA vacuuming
  • Contaminated personal protective clothing and equipment should be handled with care to prevent disturbing the silica dust and the generation of airborne silica dust
  • Washing facilities and laundering procedures must be suitable for handling silica contaminated laundry
  • Warning signs should be posted in sufficient numbers to warn of the silica hazard. There should be a sign, at least, at each entrance to the work area. The signs should display the following information in large, clearly visible letters:
    • There is a silica dust hazard.
    • Access to the work area is restricted to authorized persons.
    • Respirators must be worn in the work area.
Type 2
  • Removal of silica containing refractory materials with a jackhammer.
  • The drilling of holes in concrete or rock that is part of a tunnelling operation or road construction.
  • The use of a power tool to cut, grind, or polish concrete, masonry, terrazzo or refractory materials.
  • The use of a power tool to remove silica-containing materials.
  • The use of a power tool indoors to chip or break and remove concrete, masonry, stone, terrazzo or refractory materials.
  • Tunnelling (operation of the tunnel boring machine, tunnel drilling, tunnel mesh installation).
  • Tuckpointing and surface grinding.
  • Dry mortar removal with an electric or pneumatic cutting device.
  • Dry method dust clean-up from abrasive blasting operations.
  • The use of compressed air outdoors for removing silica dust.
  • Entry into area where abrasive blasting is being carried out for more than 15 minutes.

Full-facepiece air-purifying respirator with N-, R-, or P-series filter and 100% efficiency.

Tight-fitting powered air-purifying respirator with a high-efficiency filter.

Full-facepiece supplied-air respirator operated in demand mode.

Half-mask or full-facepiece supplied air respirator operated in continuous-flow mode.

(In addition to Type 1 measures and procedures.)

  • Other workers entering a work area where Type 2 operations are being performed should remain at least 10 metres away. Ropes or barriers should be set up to prevent unauthorized personnel from entering the work area. If this is not possible and there are workers within the 10-metre limit, the Type 2 operation should be enclosed to prevent the escape of airborne silica-containing dust ( partial or full enclosures).
Type 3
  • Abrasive blasting with an abrasive that contains ≥1 per cent silica
  • Abrasive blasting of a material that contains ≥ 1 per cent silica
Type CE abrasive-blast supplied air respirator operated in a positive-pressure mode with a tight-fitting half-mask facepiece.

Type CE abrasive-blast supplied air respirator operated in a pressure-demand or positive pressure mode with a tight-fitting full-facepiece.

(In addition to Type 1 and Type 2 measures and procedures.)

  • While abrasive blasting is in progress or the airborne dust from abrasive blasting is visible,
    • any worker entering the work area where abrasive blasting is being carried out for less than 15 minutes for inspection and/or sampling purposes should wear a half-mask particulate respirator with N-, R-, or P-series filter and 95, 99 or 100% efficiency.
    • any worker entering a work area where abrasive blasting is being carried out for more than 15 minutes should wear a respirator with a NIOSH APF of 50
    • workers engaged in cleaning dust from abrasive blasting operations, should wear a respirator with a NIOSH APF of 50
  • Where abrasive blasting is conducted, barriers, partial enclosures and full enclosures should be in place to prevent other workers from being exposed to silica-containing dust and to prevent the spread of dust to other work areas.

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Disclaimer: This web resource has been prepared to assist the workplace parties in understanding some of their obligations under the Occupational Health and Safety Act (OHSA) and the regulations. It is not intended to replace the OHSA or the regulations and reference should always be made to the official version of the legislation.

It is the responsibility of the workplace parties to ensure compliance with the legislation. This web resource does not constitute legal advice. If you require assistance with respect to the interpretation of the legislation and its potential application in specific circumstances, please contact your legal counsel.

While this web resource will also be available to Ministry of Labour inspectors, they will apply and enforce the OHSA and its regulations based on the facts as they may find them in the workplace. This web resource does not affect their enforcement discretion in any way.