Permissible exposure limit monitoring

Monitoring shall be performed. .. so that employees are not exposed to levels which exceed permissible exposure limits, or published exposure levels if there are no permissible exposure limits. ... 

Information on occupational exposure to lead is obtained primarily from the National Occupational Exposure Survey (NOES) and industry surveys of workers. While occupational exposure is widespread, environmental monitoring data on levels of exposure in many occupations are not available. OSHA has established a permissible exposure limit (PEL) for lead of 50 pg/m3 for workplace air (OSHA 1991). NIOSH has estimated that more than 1 million American workers were occupationally exposed to inorganic lead in more than 100 occupations (NIOSH 1977a, 1978a). According to NOES, conducted by NIOSH between 1980 and 1983, an estimated 25,169 employees were exposed to tetraethyl lead (not used in gasoline since December 31, 1995) approximately 57,000 employees were exposed to various lead oxides mostly in non-ferrous foundries, lead smelters, and battery plants 3,902 employees were exposed to lead chloride and 576,579 employees were exposed to some other form of lead in the workplace in 1980 (NIOSH 1990). Workers who operate and maintain solid waste incinerators are also exposed to air lead levels as high as 2,500 pg/m3 (Malkin 1992). 

The standard presents OSHA s determination that exposure to cotton dust presents a significant health hazard to employees and establishes permissible exposure limits for selected processes in the cotton industry and for non-textile industries where there is exposure to cotton dust. The cotton dust standard also provides for employee exposure monitoring, engineering controls and work practices, respirators, employee training, medical surveillance, signs and record keeping. 

Action Levels. The scheme requires that the exposures of one or more potentially-exposed workers be monitored periodically. If all of the air concentrations measured are below the "action level (AL), which is of the "permissible exposure limit" (PEL), then no further action is required unless the process is changed. The workplace is deemed to be in compliance with the standard. If a value exceeds the PEL, the workplace is declared to be out of compliance and some form of remedial action is required, e.g., a process change, engineering controls or personal protective equipment. Finally, if the sample value is between the AL and the PEL further sampling is required until two values in a row are observed below the AL (workplace in compliance) or one value is observed above the PEL (workplace out of compliance). 

The purpose of the validation program was to assure that accurate personal sampling and analytical methods would be available for use by OSHA in monitoring for non-compliance to the OSHA permissible exposure limits (PEL s). The methods are available to others who may want to use them to determine worker exposure to the substances in the OSHA regulations. 

Action Level A regulatory standard, especially used by the United States Occupational Safety and Health Administration (OSHA) for air contaminants, to indicate an unhealthy concentration of a substance. The US action level for arsenic in air is 5 mg m-3 averaged over an eight-hour period (29 Code of Federal Regulations 1910.1018). If an action level is exceeded, efforts must be made to protect individuals from exposure to the contaminant, reduce the concentration, and possibly monitor or treat exposed individuals. In general, action levels are 50 % of the permissible exposure limit (PEL) (compare with threshold limit value). 

Figure 3.2 NIOSH-recommended employee exposure determination and measurement strategy. AL — action level PEL = permissible exposure limit. OSH A Laboratory Standard 29 CFR 1910.1450 requires employee notification of any monitoring results...

OSHA s laboratory chemical standard made simple. Chemical Hygiene Plan, hazards identification, safe lab practices, permissible exposure limits, exposure signs and symptoms, monitoring, and recordkeeping. 

Other OSHA standards setting forth permissible exposure limits (PELs) apply to the extent that they require limiting exposures to below the PEL and, where the PEL or "action level" is routinely exceeded, the Laboratory Standard s provisions require exposure monitoring and medical surveillance. The requirements for exposure monitoring and medical surveillance are found in Appendix A, sections (d) and (g) of the Laboratory Standard. 

Ceiling limit is an airborne concentration of a toxic substance in the work environment that should not be exceeded. In threshold limit value (TLV) and permissible exposure limit (PEL), or recommended exposure limit (REL), the maximum allowable concentration to which an employee may be exposed. If instantaneous monitoring is not feasible, then the ceiling is a 15-minute time-weighted average exposure not to be exceeded at any time during the working day. 

Measuring acid concentration is important for many applications, specifically for space and homeland security applications. Hydrochloric acid is released from the exhaust plume of solid rocket motors that use ammonium perchlorate as the rocket propellant. This plume can be dangerous in high concentrations and monitoring its concentration and dispersion are important tasks. Hydrochloric acid and other acid gases like nitric acid and hydrofluoric acid are also important and very dangerous toxic industrial chemicals and need to be monitored because of their low permissible exposure limits. 

Termination of monitoring, (i) If the periodic monitoring required by paragraph (f)(3) of this section reveals that employee exposures, as indicated by statistically reliable measurements, are below the permissible exposure limit and excursion limit the employer may discontinue monitoring for those employees whose exposures are represented by such monitoring. 

Accuracy of measurement. The employer shall use a method of monitoring and analysis that has an accuracy of not less than 25 percent ( 25 percent), with a confidence level of 95 percent, for airborne concentrations of cadmium at or above the action level and the permissible exposure limit. 

Frequency, (i) If the monitoring required by this section reveals employee exposures to be below the permissible exposure limit, the employer shall repeat these measurements at least quarterly. 

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