Existing Chemical Exposure Limits under TSCA
The Toxic Substances Control Act (TSCA) gives EPA the authority to take action to address unreasonable risks to public health or the environment from chemicals currently on the market. Where a chemical presents an unreasonable risk to human health in the workplace, EPA may develop an occupational exposure limit, known as an Existing Chemical Exposure Limit (ECEL), as part of a chemical management program to address worker risk.
On this page:
- What is an Existing Chemical Exposure Limit (ECEL)?
- Why would EPA require an Existing Chemical Exposure Limit (ECEL)?
On other pages:
- List of Final and Proposed Existing Chemical Exposure Limits (ECELs) under TSCA
- New Chemical Exposure Limits (NCELs)
What is an Existing Chemical Exposure Limit (ECEL)?
An Existing Chemical Exposure Limit (ECEL) is a regulatory occupational exposure limit (OEL) set by EPA to limit inhalation risks to workers exposed to certain chemicals in a workplace. The ECEL is a maximum average airborne concentration of the chemical that someone can be exposed to in the workplace without experiencing unreasonable risk from inhalation exposure to the chemical. Similar to other OELs, e.g., Permissible Exposure Limits (from the Occupational Safety and Health Administration), the ECEL is typically expressed as an 8-hour time-weighted average (TWA). EPA may also propose or set an EPA Short-Term Exposure Limit (EPA STEL), expressed as a 15-minute TWA.
ECELs apply to chemicals already on the TSCA Inventory, which are referred to as existing chemicals, and regulated under TSCA section 6. There are also New Chemical Exposure Limits (NCELs) under section 5 of TSCA.
Why would EPA require an Existing Chemical Exposure Limit (ECEL)?
As part of a TSCA section 6 risk management rule, EPA may require an ECEL as an interim control prior to prohibition or as part of a Workplace Chemical Protection Program (WCPP) to ensure workers and others in the workplace, referred to as potentially exposed persons, are protected from serious health risks from inhalation exposures of certain chemicals. The WCPP requires certain actions to mitigate occupational risk from chemical exposures, including, as appropriate, a regulatory occupational exposure limit (e.g., ECEL or EPA STEL).
As part of a WCPP, owner/operators must ensure that potentially exposed persons are not exposed to concentrations of workplace chemicals above the ECEL. This can be accomplished by following the hierarchy of controls, including implementing engineering controls, administrative controls, and/or using personal protective equipment as exposure control measures.