New chemical exposure limits NCELs

Some of the model 5(e) orders have provisions for new chemical exposure limits, (NCELs) that can be implemented instead of using respirators to limit risks from inhalation of the PMN substance. NCELs are specific numerical limits on the airborne concentrations of the PMN substance. The EPA may develop a maximum concentration for eight hour exposures, a maximum concentration for work shifts that are shorter or longer than eight hours, and a short term exposure limit (STEL) for fifteen minute exposure periods. In order to use NCELs instead of respirators, the signatory must develop a sampling and analytical plan and have it verified by an independent third party laboratory. As of 2002 the EPA had developed thirty four NCELs. ... 

New chemical exposure limits (NCELs) for new chemicals regulated under TSCA are modeled after OSHA s permissible exposure limits (PELs) for workers exposed to a substance by inhalation. NCELs may include an eight-hour time weighted average limit or a short-term exposure limit for a chemical substance. In 1995, the US EPA described the risk basis for determining... 

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