Inspection Unit 2B

Equipment and Tools

The following two lessons were written by Todd F. Lewis CIH (52 N. 3167 E. Idaho Falls, ID 83402 (208) 524-9146). I would like to thank Todd Lewis for permission to reprint his articles here.  They were both originally published in Wildlife Control Technology Magazine. To learn about the magazine, visit

Basic Respiratory Protection

Disclaimer: This article is not an all-inclusive guide; a Certified Industrial Hygienist should be consulted for further information. In addition, since the writing of this article, it is highly recommended and and, in many cases, may be required that anyone using a respirator must have a medical evaluation and a fit test.  

Respiratory protection in general can be a highly complex and technical issue. The average NWCO needs to be protected but does not have the time or likely the desire to study this subject in depth. full face respirator as worn by Alan Huotr. Photo by Stephen M. VantasselHis or her time is probably better spent actively marketing or directly on the job. The following is a brief overview of respiratory protection as it apples to the NWCO; it is not intended to be all-inclusive in content or scope. No attempt will be made to touch on respiratory protection from chemicals such as pesticides or rodenticides or the use of air-supplied respiratory protection.

Note the more advanced full-face protection provided by the mask shown at right. Photo by Stephen M. Vantassel.

The occupation of the NWCO is somewhat unique to the working world. In most occupations when a potentially dangerous material becomes airborne, the primary means of preventing injury is through the use of engineering and work practice control measures. This usually involves the use of exhaust ventilation and /or worker isolation to prevent exposure. These measures are not normally available or feasible in the case of the NWCO. In fact, as NWCOs we actually seek out tight places that are inherently contaminated with potentially dangerous microorganisms/particulate. Potentially hazardous microorganisms include, but are not limited to, various viruses, parasites, bacteria, rickettsia, fungi, and allergens of biological origin and by-products of microbial growth. Routine hand-washing practices and the use of gloves and other protective equipment can significantly reduce the risk of exposure by ingestion and dermal routes. The respiratory system is by far the most vulnerable. This is due to its direct association with the circulatory system. Because microorganisms are invisible to the naked eye and frequently otherwise undetectable, they are considered silent killers.

After enactment of the Occupational Safety and Health Act (OSHA), the National Institute for Occupational Safety and Health (NIOSH), and the U.S. Bureau of Mines (USBM), which would later become known as the Mine Safety and Health Administration (MSHA), were charged with respirator testing and approval. Only NIOSH-MSHA-approved respirators are now recognized as approved devices by the general public. Once an approval device has been obtained, the user should become INTIMATELY acquainted with the limitations of the device as set forth in the approval. The device should never be used beyond the limitations and conditions established by NIOSH and the manufacturer. The user should never alter the device in anyway or use parts interchangeably from other manufacturers. This is not the same as using a brand-X oil filter on a brand-Z car. To draw this correlation in the world of respiratory protection invites disaster.

Proper selection of respiratory protection depends on the toxic substance involved, conditions of exposure, human capabilities, and equipment fit. Most NWCOs will want to generally protect against the uglies mentioned above as well as nuisance particulate (dust bunnies) and fibrous aerosols (asbestos and fiberglass). The primary device used for this application is the mechanical-filter respirator; specifically those fitted with High Efficiency Particulate Airfilter (HEPA).

NOTE: The HEPA Filtered Respirator does NOT supply oxygen or remove gases, vapors or oxygen deficiency. Respirator face-pieces come in 2 general configurations, the half-face and the full-face. The half-face-piece is lighter, cheaper, tends to lose a seal when heavy perspiration occurs, is less effective in heavily contaminated environments and does not provide eye protection. The full-face-piece is heavier, more expensive, less likely to loose a seal when heavy perspiration occurs, is more effective in highly contaminated environments and provides built in eye protection.

Human capabilities should not be overlooked. Tell your physician at your annual checkup (Yes, you should get one) that you will be wearing a negative pressure respirator requiring you to physically move air through the filters with your lungs. Include what other stressors you may encounter on the job also, such as ladder climbing, crawling, animal handling, work from heights, special chemicals you may use, repetitive motion, and so forth. Ask him/her if they feel you are physically fit to work in a respirator.

As a respirator wearer you should read and understand the manufacturers instructions of use, inspection, storage maintenance, repair and fit test. All equipment should be inspected before and after use. Maintenance should be performed regularly and include washing, sanitizing, rinsing, drying, inspection for defects, replacement or worn or deteriorated parts, and proper storage to prevent damage. The manufacturer will call out certain fit testing protocol, which generally consist of positive and negative pressure testing.

I hope this information provides a good overview for the NWCO. Respiratory protection when coupled with other good hygiene practices provides the operator with a safety envelope that is the best insurance that you will return home at the end of the day injury and illness free.

Advance to Unit 2C

©2005 Stephen M. Vantassel