OHS Code Explanation Guide

Published Date: July 01, 2009
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Part 18 Personal Protective Equipment

Section 244 Respiratory dangers

Subsection 244(1) Need for hazard assessment

If a worker is or may be exposed to one or more of the listed conditions i.e. (1) exposure to an airborne contaminant (usually a chemical) exceeding the contaminant’s OEL; (2) an oxygen deficient atmosphere; or (3) exposure to an airborne biohazardous material, the employer must assess the work site to determine if workers need to use respiratory protective equipment. Subsection (2) lists the factors that the employer must consider when doing this assessment.

Subsection 244(2) Factors to consider

This subsection lists the factors to be considered when performing the hazard assessment required by subsection (1). In previous editions of the OHS Code, the inclusion of biohazardous materials was implied. This edition of the OHS Code explicitly requires the employer to take into account the nature and exposure circumstances of airborne biohazardous materials.

Examples of situations in which workers may require respiratory protection against exposure to airborne biohazardous materials include

(a) sewage plant workers exposed to aerosols created during effluent processing or during equipment maintenance,
(b) laboratory workers exposed to aerosols while handling biohazardous materials,
(c) health care workers exposed to airborne biohazardous materials,
(d) rendering plant workers exposed to aerosols created during materials processing,
(e) workers involved in renovations removing mouldy building materials, and
(f) workers stirring up dusts containing waste products from animals such as birds, bats and mice. These contaminated dusts may contain materials that could cause disease in humans.

The OHS Code defines a “biohazardous” material as a pathogenic organism, including a bloodborne pathogen, that, because of its known or reasonably believed ability to cause disease in humans, would be classified as Risk Group 2, 3 or 4 as defined by the Public Health Agency of Canada, or any material contaminated with such an organism.

Subsections 244(3) and 244(4) Nature and exposure circumstances of airborne biohazardous materials

Many factors affect the nature and exposure circumstances of a worker’s exposure to an airborne biohazardous material. These include

(a) the type of biological agent,
(b) the route of transmission,
(c) the pathogenicity of the agent,
(d) concentration of the agent,
(e) size of airborne particles,
(f) duration of exposure,
(g) work activity, and
(h) work practices and procedures for which exposure to biohazardous material is possible.

Item (e), size of airborne particles, deserves additional discussion. Droplets are relatively large particles which, because of their size and mass, travel a short distance through air, usually no further than 2 metres. Most droplets land on inanimate objects and do not pose a respiratory hazard.

Inhalable infectious airborne particles that remain aloft because of their small size and low mass do present a potential respiratory hazard to workers. These particles may be generated during coughing and sneezing, during some medical procedures, and by the aerosolization of liquids and stirring up of dusts containing biohazardous materials.

The presence of an airborne biohazardous material is not, of itself, sufficient to cause illness in an exposed worker. The pathogenicity of the material, the exposure concentration, the health status of the exposed worker and the presence of a respiratory route of transmission need to be evaluated.

The following factors should be considered when determining the need for respiratory protective equipment:

(a) Who is potentially exposed to the biohazardous material as part of their work?
(b) What are the potential sources and routes of transmission to workers?
(c) Which job tasks increase the potential for worker exposure to biohazardous material at the workplace?
(d) Can the biohazardous material be spread to workers through airborne transmission?

Subsection 244(3) Provide and ensure availability

Based on the employer’s assessment required by subsection (1), the employer is responsible for providing workers with the appropriate respiratory protective equipment. The employer must also ensure that the equipment is available to workers who need to use it.

Paragraph (b) explicitly deals with airborne biohazardous materials. The OHS Code relies on CSA Standard Z94.4-02, Selection, Use and Care of Respirators, for establishing the criteria to be used by employers to select respirators. Unfortunately, the CSA Standard does not specify selection criteria for biohazardous materials, hence the need for paragraph (b) and its cross-reference to section 247 and the CSA Standard.

Paragraph (b) specifically requires that respiratory protection be provided and made available when the effects of worker exposure to airborne biohazardous materials are unknown i.e. the health effects and mechanism of transmission have not yet been characterized, and no procedures are in place to effectively limit exposure. Unknown exposure effects include adverse health effects such as an acute or chronic illness, acute or chronic disease, or death.

This approach to respiratory protection is based on the principle that precautions need to be taken until sufficient information is available to indicate that different precautions are acceptable or necessary. The worker’s “exposure circumstances” may influence the type of respiratory protection required.

A worker’s “exposure circumstances” may be such that respiratory protective equipment is unnecessary because exposure is effectively limited through the use of one or more of the control strategies listed in subsection (3.1), or other equally effective strategies. Readers are directed to the previous explanation dealing with the Nature and exposure circumstances of airborne biohazardous materials for additional discussion regarding “exposure circumstances”.

Subsection 244(3.1) Procedures to limit exposure

If the employer has developed and implemented procedures and safe work practices that effectively limit exposure to the biohazardous material, respiratory protective equipment is not required. Examples of how exposure can be effectively limited include

(a) containment of the source biohazardous material to prevent airborne spread,
(b) collection of airborne materials at their source of generation i.e. local exhaust system or laboratory fume hood that redirects airborne materials away from workers,
(c) isolating workers from the biohazardous material by distance, time or a combination of both,
(d) dust suppression equipment and wetting, and
(e) isolation or negative pressure containment rooms, etc.

The employer must be able to demonstrate that exposure to airborne biohazardous material has been effectively limited.

Subsection 244(4) Worker responsibility

The worker is required to use the appropriate respiratory protective equipment provided by the employer.

For more information
Respiratory Protective Equipment: An Employer’s Guide
Bulletin PPE001