Evaluate Employees' Exposures to Each Hazard
After you have identified respiratory hazards, evaluate employees' exposures to determine whether they are exposed to unsafe levels.
NIOSH Health Hazard Evaluations
Evaluate exposures by measuring them or estimate them with data from previous exposure measurements. Three examples:
- Measure the exposures of individual employees by sampling their breathing air. The procedure - called personal exposure monitoring - is the most accurate way to evaluate exposure levels.
- Sample the air at specific locations - called area monitoring - to estimate exposures affecting groups of employees. This method is useful when employees move about and may not always be near a hazard's source.
- Use representative exposure data from industry studies, trade associations, or product manufacturers to estimate exposures affecting groups of employees. You must be able to show that the data are based on conditions similar to those that exist in your workplace.
Immediately dangerous to life and health (IDLH) refers to an atmospheric concentration of a toxic, corrosive, or asphyxiant substance that poses an immediate threat to life, causes irreversible health effects, or interferes with one's ability to escape from a dangerous atmosphere. If employees may be exposed to such substances and you are unable to evaluate their exposures, you must consider the exposure immediately dangerous to life and health.
About Exposure Monitoring
Exposure monitoring is the testing of air samples to determine the concentration of contaminants in a work environment. Test data from the samples are averaged over a period of time, usually eight hours, and referred to as a time-weighted average (TWA).
OSHA has established permissible exposure limits (PEL) for specific air contaminates. Exposures must not exceed the eight-hour PEL-TWA in any eight-hour work shift.
Permissible exposure limits are listed in OSHA Standard 1910.1000, Table Z-1 Limits for Air Contaminants, Table Z-2 Toxic and Hazardous Substances, and Table Z-3, Mineral Dusts.
A trained specialist, such as an industrial hygienist, can help you evaluate employee exposures, interpret the results, and suggest how to lower exposures to safe levels.
Knowledge Check Choose the best answer for the question.
1-3. Which of the following is the most accurate way to evaluate exposure levels?
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