University Resources, Operations and Policies


Section 4

4.0 Controlling Chemical Exposures

The Laboratory Standard requires the employer to determine and implement control measures to reduce employee exposure to hazardous chemicals; particular attention must be given to the selection of control measures for chemicals that are· known to be extremely hazardous. There are three major routes of entry for a chemical to enter the body: inhalation, absorption, and ingestion. Three types of controls for prevention of these various routes of entry include engineering controls, personal protective equipment, and administrative controls. Each route of entry a chemical can take to enter the body can be controlled in a number of ways, as explained below.

4.1 Inhalation Hazards
Inhalation of chemicals is the most common route of entry a chemical can take to enter the body. To avoid inhalation exposures, hazard reduction methods such as substituting a less volatile or a less toxic chemical or substituting a liquid or solid chemical for a gaseous one are the best means of control. If substitution is not practical, engineering controls such as ventilation should be used to lessen the chance of exposure. The use of well-functioning local exhaust ventilation such as laboratory chemical hoods, biological safety cabinets, vented glove boxes, and other local exhaust systems is often required to minimize exposure to hazardous chemicals. Dilution ventilation may be used to reduce exposure to nonhazardous nuisance odors. For extremely toxic chemicals such as those classified as poison gases by state or federal agencies (e.g., arsine, phosphene), the use of closed systems, vented gas cabinets, fail-safe scrubbing, detection, or other stricter controls may be required.

If both substitution and engineering controls are unavailable, the use of personal protective equipment may be required to reduce inhalation exposures. Respiratory protection from dust masks to self-contained breathing apparatus may be utilized to this end. If laboratory employees wear respirators, requirements of the OSHA Respirator Standard (1910.134) must be met and a written respirator program must be implemented. This Standard requires training on the proper use of respirators, medical surveillance to ensure the user is capable of wearing a respirator, and fit-testing to ensure that the respirator fits properly. A laboratory worker or his/her supervisor should contact the Coordinator of Environmental Health and Safety (877.3242) in the event that respiratory protection is to be utilized to control exposures to hazardous chemicals.

In addition, the following principles should be utilized to reduce the risk of exposure to hazardous chemicals:

  • Minimization of exposure time for individual employees;
  • Restricted access to an area where a hazardous chemical is used; and
  • Proper signage on laboratory doors to indicate special hazards within


Joseph Landesberg, Ph.D.
Chemical Hygiene Officer
p – 516.877.4148
e –

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