In all Canadian jurisdictions, employers are responsible for ensuring a healthy and safe work environment for employees. This includes making appropriate control measures available to protect workers from exposure to hazardous agents. The CSMLS endorses the use of a hierarchy of controls – engineering, administrative and personal protective equipment – to prevent injury and illness. In potential infectious disease outbreaks, engineering and administrative controls will be most effective and should be implemented first. In addition, as the “last line of defence,” personal protective equipment should be chosen to provide adequate protection from the specific hazardous agent.

In the World Health Organization’s (WHO) most recent edition of their Laboratory Biosafety Manual (third edition, 2004), it is stated “Advice should be sought from a suitably qualified person, e.g. an occupational hygienist, for selection of the correct respirator. Surgical type masks are designed solely for patient protection and do not provide respiratory protection for workers.”

Recent concerns about a potential influenza pandemic have heightened awareness concerning respiratory protection for health care workers. Respiratory exposure to infectious agents is dependant on several factors, including the size of infectious particles, the concentration of infectious agents in the aerosol, the persistence of the aerosol, and the length of exposure time. Not all of these factors are immediately known when an infectious respiratory outbreak occurs. In keeping with WHO recommendations, the CSMLS supports the use of N-95 respirators as the minimum level of protection for laboratory personnel who may be exposed to bioaerosols through close contact with infected patients, or in the performance of laboratory tests on potentially infectious specimens.

The CSMLS believes that all laboratories should have a plan in place that is defensible and ensures due diligence in the protection of workers. Until enough evidence is available to support changes to current best practice, N95 respirators should be used as the minimum standard for health care workers facing potential exposure to respiratory infectious agents. The majority of scientific studies on the efficacy of these respirators supports their superiority over standard surgical masks in the reduction of exposure to airborne and droplet contamination.

Approved by CSMLS Board of Directors, May 27, 2006