On November 15, 2014, a chemical leak at a plant in Texas killed four workers. An investigation1 revealed a clogged pipe leading from a storage tank of methyl mercaptan. The toxic liquid was responsible for claiming the lives of the workers, who were not required to wear respirators.2
While the investigation continues, the incident serves as a red flag to those working around hazardous substances, infectious agents, fumes and gases, and other airborne risks. Without proper protection, the danger is real and the hazards can be fatal.
OSHA classifies respirators as air-purifying (those that remove contaminants) and atmosphere-supplying (those that supply clean air to wearers).
Air purifying respirators
While dust masks may be helpful to protect users from allergens, dust, and mists, they do not provide adequate filtration for gases, vapors, asbestos, and lead.
Half-face respirators are the first level of protection against these contaminants. Full-face respirators provide an enhanced level of protection and also shield the eyes. Loose-fitting powered air-purifying respirators circulate air within a hood or helmet. All of these types of respirators filter air through cartridges, which are selected according to the user’s exposure to contaminants. Cartridges must be monitored and changed when necessary. Typically, these respirators are National Institute for Occupational Safety and Health (NIOSH) approved.
Atmosphere-supplying respirators
For oxygen-deficient environments, a self-contained breathing apparatus (SCBA) with an air tank keeps wearers breathing clean air. SCBAs are donned when the air is deemed dangerous prior to entry. Those working with very toxic chemicals or unknown contaminants should be outfitted with a SCBA. Regular SCBA wearers include firefighters, rescue workers, and industrial users.
NIOSH approves SCBA after rigorous testing and evaluation. These tests include the ability to protect users from chemical, biological, radiological, and nuclear materials that first responders may encounter.
Matching Filters with Contaminants
Filters capture contaminants and prevent wearers from breathing in potentially toxic substances. They are color-coded according to the type of contaminant. The color-coding system is identical across manufacturers but the cartridges themselves are not interchangeable.
| Color | NIOSH-approved for use with: |
| White | Acid gas |
| White/Yellow | Chlorine |
| White/Green Stripe | Hydrocyanic acid gas |
| Yellow; Yellow/Pink | Organic vapors, chlorine, hydrogen chloride, sulfur dioxide, chlorine dioxide, hydrogen fluoride |
| Orange; Orange/Pink | Organic vapors, chlorine, ammonia, methylamine, hydrogen chloride, sulfur dioxide, chlorine dioxide, hydrogen fluoride, hydrogen sulfide (esc), formaldehyde |
| Green; Green/Pink | Certain organic vapors, chlorine, hydrogen chloride, chlorine dioxide, sulfur dioxide, hydrogen sulfide (escape only), ammonia, methylamine, formaldehyde†, or hydrogen fluoride |
| Olive | Multi-contaminants and CBRN agent |
| Blue | Carbon monoxide |
| Teal | Dust, fumes, and mists; any particulates free of oil |
| Magenta | Radioactive materials (except tritium and noble gases) |
| Purple | Any particulates—P100 |
| Brown | Acid gases, organic vapors, and ammonia gases |
| Black | Certain organic vapors |
†When used for protection from formaldehyde, OSHA requires that gas-proof goggles be worn in addition to half-face mask respirators.
Mastering the Fit
Any respirator is only effective when it fits and is worn properly. For this reason, OSHA requires employers to fit test workers who must use respirators on the job. Respirator styles vary, and those that form a tight seal against the face or neck can allow contaminated air in if they do not fit properly.
Physical changes, such as weight gain or facial or dental surgery can also affect the fit of the respirator over time. OSHA3 details both qualitative and quantitative tests to determine if the respirator fit is sufficient. Cleaning and maintaining respirators is also necessary to keep them functioning optimally.
For SCBA, other criteria apply as well. Wearers must be trained in the use and testing of SCBA. It is important to follow the manufacturer’s directions precisely as gauges and valves must be checked.
View our selection of respirators and masks.
1Safety+Health. “CSB Investigates Fatal Chemical Leak at Texas Plant.” Retrieved from http://www.safetyandhealthmagazine.com/articles/11425-csb-investigates-fatal-chemical-leak-at-texas-plant on February 24, 2015.
2Safety+Health. “Repeat of Recent DuPont Incident ‘Can Happen Anywhere,’ CSB Chairman Warns.” http://www.safetyandhealthmagazine.com/articles/11532-repeat-of-recent-dupont-incident-can-happen-anywhere-csb-chairman-warns on February 24, 2015.
3OSHA. “Respirator Fit Testing.” Retrieved from https://www.osha.gov/video/respiratory_protection/fittesting_transcript.html on February 24, 2015.
