Toxicants ERPGs

Measures of inhalation toxicity include ERPG, TLV, TLV-STEL, TLV-TWA, PEL, and IDLH. 

A system of guidelines for air concentrations of toxic materials prepared by the American Industrial Hygiene Association. An ERPG is the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to 1 hour with the following results ... 

ERPG data are shown in Table 5-6. To date, 47 ERPGs have been developed and are being reviewed, updated, and expanded by an AIHA peer review task force. Because of the comprehensive effort to develop acute toxicity values, ERPGs are becoming an acceptable industry/ government norm. 

TABLE 23 16 ERPG Values and Other Toxicity Values for Toxic Materials... 

Other means of evaluating the toxic effects of vapors, and their potential impact on exposed people, can be found in the Emergency Response Planning Guidelines for Air Contaminants (ERPGs), issued by the American Industrial Hygiene Association (1992). The documents define values of exposure to toxic vapors needed to produce specific health effects. Three levels of vapor concentration are defined ... 

For illustrative purposes, the hazardous properties of the materials used in the examples have been modeled to the Emergency Response Planning Guideline, ERPG-2 (see Section 3.1.1) concentration for toxic materials, or to one half of the lower flammable limit (LFL/2) for flammable material. Lastly, only the first 3600 seconds of the event are considered in these examples. For an actual situation, different concentration levels for toxic or flammable concentrations may be considered and different durations as well. 

Table 17.4 provides values of K, a, and b for the equations for neutral and dense gases and vapors, rural and urban environments, short-dmation releases (10 min), long-duration releases (30 min), and short distances and great distances. Values of EPA toxic endpoints for the EPA listed materials are presented in Appendix A. Also shown are values of toxic endpoints for OSHA-listed materials, based on (in order) ERPG-2 values, 1/10 of the IDLH, or 1/100 of the 4-hour LC50. 

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