Choosing Respiratory Protection for Infectious Agents
By Jeffery C. Camplin, CSP, CPEA

Not all respirators are created equal.

Over the last few years, outbreaks of SARS ( severe acute respiratory syndrome), MRSA ( methicillin resistant staphylococcus aureus) , avian flu and tuberculosis have been reported in the media on a frequent basis. These reports often show workers and the general public using respirators that span from the limited protection of a surgical mask to the extreme protection provided by self-contained breathing apparatus. Selecting proper respiratory protection for these highly infectious agents can be challenging.

Surgical Masks vs. N95 respirators

Surgical masks and filtering face piece respirators are used to cover the mouth and nose against splatter by or exposure to body fluids, such as blood, respiratory secretions, vomit, urine or feces). Surgical masks are recommended for use by medical staff with patients infected with avian flu or MRSA with a productive cough. Surgical masks should also be worn by healthcare workers to prevent exposure of mucous membranes of the mouth and nose during procedures that are likely to generate droplets of blood or body fluids requiring universal precautions.

Outside the healthcare and medical transport settings, the Centers for Disease Control and Prevention (CDC) do not recommend the routine use of respirators for protection from SARS. Surgical masks are also not recommended for use by the general public against avian flu or MRSA. Most people who develop MRSA, SARS or avian flu do not become infected by breathing contaminated air. The best protection from SARS and other infectious agents in public places, including workplaces other than healthcare and medical transport settings, is to wash your hands frequently and avoid touching your eyes or nose.

Recent CDC infection control guidance documents provide recommendations that certain healthcare workers protect themselves from diseases potentially spread through the air, such as SARS or tuberculosis, by wearing a fit-tested respirator at least as protective as a NIOSH-approved N95 respirator. An N95 respirator is one of nine types of disposable particulate respirators. Particulate respirators are also known as "air-purifying respirators" because they protect by filtering particles out of the air you breathe. Workers can wear any one of the “NIOSH-approved” particulate respirators for protection against diseases spread through the air if they have been properly fit tested and maintained.

NIOSH-approved disposable respirators are marked with the manufacturer's name, the part number (P/N), the protection provided by the filter (e.g. N95), and "NIOSH." Personal protective equipment that is intended for use in preventing or treating disease is also subject to regulation under the device provisions of the Federal Food, Drug, and Cosmetic Act. This includes surgical masks, surgical N95 respirators, medical gloves, and surgical gowns. Before these devices can be sold in the United States , the Food and Drug Administration evaluates the manufacturer's new product applications to make sure that the devices are similar to existing products already on the market.

Understanding Protective Limitations

CDC recommends the use of surgical masks or N95 respirators based on the pathways through which specific diseases are transmitted. A surgical mask is not a respirator. It is designed to protect from splatter by body fluids, such as blood, respiratory secretions, vomit, urine or feces. Surgical masks worn by workers also help protect patients during surgery and when a healthcare worker is caring for an open wound or if the healthcare provider is sick.

Particulate respirators provide protection against certain size airborne particles . They are the simplest, least expensive, and least protective of the respirator types available. These respirators do not protect against other workplace hazards such as chemicals, gases or vapors. The commonly known "N95" filtering face piece respirator is one type of particulate respirator, often used in hospitals to protect against infectious agents. Surgical masks are not designed for use as particulate respirators and do not provide as much protection as a filtering face piece N95 respirator. Most surgical masks do not effectively filter small particles from air and do not prevent leakage around the edge of the mask when the user inhales.

Use of Surgical Masks

Surgical masks are only recommended for use as a last resort for those healthcare and medical transport workers exposed to SARS patients when no NIOSH-approved respirator equivalent to or greater than the N95 is available. SARS appears to be transmitted mainly through direct contact with infectious materials, including large respiratory particles, and surgical masks will provide barrier protection against droplets that are considered to be the primary route of SARS transmission. However, surgical masks may not adequately protect against aerosol or airborne particles, primarily because they do not effectively filter small particles from the air, they allow leakage around the mask, and they cannot be fit tested. Because scientists cannot currently rule out the spread of SARS through the air, CDC recommends a NIOSH-approved respirator equivalent to or greater than the N95. An N95 respirator will provide the same protections as a surgical mask and also protect against very small particles, such as fine aerosolized droplets produced by coughing. The N95 respirator will also provide protection against persons with known or suspected pulmonary and laryngeal tuberculosis.

OSHA Compliance

Employers providing respiratory protection must establish a written program that provides employees with medical clearance, training and fit-testing prior to use. Employers who allow their employees to wear filtering face piece N95 respirators on a voluntary basis must implement limited provisions of a respiratory protection program. When a filtering face piece respirator such as an N95 is the only protection used, the employee must be provided a copy of Appendix D of OSHA's Respiratory Protection Standard, 29 CFR Part 1910.134. For all other voluntary users, an additional written respirator program that covers medical fitness and proper maintenance procedures must be implemented.

Jeffery C. Camplin, CSP, CPEA, is president of Camplin Environmental Services, Inc. Contact him at (847) 292-1190; E-mail: mundycamp@aol.com