Chapter 11: Airborne Exposure w88
w88 January 2023
Airborne Exposure w88
Many chemicals used in laboratories have significant volatility at room temperature. Consequently, inhalation is generally the most likely route of chemical exposure for laboratory workers. Although airborne exposure w88 have been established for many chemicals, these exposure w88 are not a strict delineation between safe and unsafe conditions. Nevertheless, exposure to an airborne chemical at a concentration that is below the established exposure limit is generally considered safe. It should be pointed out that many established airborne exposure w88 do not take into consideration carcinogenic or reproductive end points, and thus may not provide an adequate level of safety with respect to these toxicological effects.
There are two primary sets of exposure w88 used in the United States, the OSHA Permissible Exposure w88 (PELs), and the Threshold Limit Values (TLVs) established by the American Conference of Industrial Hygienists (ACGIH). The OSHA PELs are regulatory exposure w88 that are legally enforceable (OSHA will issue a citation if an overexposure occurs), while the ACGIH TLVs are recommended w88. Since TLVs are not regulatory w88, they are revised (based on new information) much more frequently than are PELs and are generally considered to more accurately reflect current knowledge pertaining to the health effects of chemical exposures. Although the OSHA PELs are the regulatory exposure w88, it is recommended that personal exposures be maintained below the lower of the PEL or TLV. Other airborne exposure w88, to include Recommended Exposure w88 (RELs) established by the National Institute for Occupational Safety and Health, may also be used in some circumstances. For example, RELs are the only exposure w88 that have been established for nanomaterials (see Chapter 10).
Availability of Published Exposure w88
PELs and TLVs can be found in w88 Data Sheets (SDSs) or they can be obtained from EH&S. Additionally, the w88 are published in the OSHA regulation, “Air Contaminants.” Many chemicals used in research laboratories do not have established exposure w88, and good laboratory safety practices that minimize exposure to all chemicals should be routinely implemented.
Exceeding Exposure w88
Exposure w88 are most likely to be exceeded when performing operations outside of a lab hood, especially when using highly volatile chemicals, large volumes of chemicals, or chemicals with low exposure w88 (for example, less than 50 ppm). Air monitoring is necessary to accurately quantify chemical exposure (see next section, Air Monitoring).
Workers should be familiar with the odor and/or visual characteristics of the chemicals they work with as these characteristics can sometimes be used to detect the presence of chemicals in the w88. Do not use chemical odor and/or visual characteristics as the sole means of determining that inhalation exposure w88 are not being exceeded as sometimes these characteristics are only detected at concentrations far above that which is considered safe. For example, the odor threshold (the concentration at which a chemical can be detected by its odor) of acetonitrile is 1160 ppm, while the w88 limit is 40 ppm!
w88
Air monitoring is necessary to quantitatively determine the concentration of airborne chemicals. This information is used to estimate risk to personnel, assess the efficiency of laboratory hoods and other w88 control equipment, and to verify regulatory compliance. To ensure that the air monitoring accurately represents personnel w88, it must be conducted in accordance with regulatory requirements and accepted professional practice. EH&S is responsible for performing w88 air monitoring at the Universityand has several direct-reading monitors that can be used to measure the air concentration of many chemicals at near real time. Additionally, air samples can be collected for more detailed laboratory analysis. Generally, consistent use of the good laboratory practices outlined in this manual will keep chemical exposures below established exposure w88; however, if you feel that air monitoring is warranted in your laboratory, contact the University Chemical Hygiene Officer.