Degreasing and Fireworks

In line with Independence Day fireworks, here’s breaking news!

The U.S. EPA is taking steps that will likely severely restrict use of chlorinated and brominated solvents used by manufacturers in critical cleaning and degreasing.

On June 30, the EPA announced that they are revising their risk assessment for perchloroethylene (PCE). The announcement again refers to an unreasonable, unquantified risk to workers, notably through inhalation. Where does unreasonable become reasonable? Industry can realistically manage risks if the people involved know levels to aim at. We therefore launched an expedition in search of worker exposure numbers.

We found numbers! In contrast with OSHA PEL (Permissible Exposure Limit), EPA uses the acronym ECEL (existing chemical exposure limit). We suggest you review the inhalation limits developed by the EPA.

Here are the 8-hour worker exposure inhalation limits for chlorinated and brominated solvents. Note that for Methylene Chloride, there is also a 15 minute Short Term Exposure Limit (STEL).

The wording of the documents is somewhat similar. “EPA has developed an 8-hour existing chemical exposure limit (ECEL) in support of risk management efforts on trichloroethylene under TSCA section 6(a) … EPA has calculated the ECEL to be 4.0 ppb (0.021 mg/m3) for inhalation exposures to trichloroethylene as an 8-hour time weighted average (TWA) and for use in workplace settings…”

Today’s announcement about PCE changes the nature of the assessment of PCE to a “whole chemical approach,” rather than on a use-by-use basis. The whole chemical approach appears to put the burden of proof on industry to demonstrate that control methods would reduce the risks to an acceptable level. In this update, EPA does not assume that workers always wear or use appropriate Personal Protection Equipment (PPE). We expect similar revisions will be proposed for the other risk assessments.
In terms of engineering controls, we know that “airless” cleaning systems have very low emissions to the air. Those who manufacture such systems (and those who use them routinely) might find it in their best interest to determine and demonstrate that achieved worker exposure limits can reliably be kept below the ECEL.

Before changing any cleaning process consider the costs and implications of any change to your cleaning process. We’ve said it before; we’ll say it again: be watchful; don’t panic – the rules have not been finalized. Learn the options and make the best choice for your application. We will continue to provide you with our best independent information about critical cleaning processes.

Here are the links to download the documents.
June 30, 2022 announcement, PCE risk assessment
methylene chloride ECEL
n-Propyl Bromide ECEL
Perchloroethylene ECEL
Trichloroethylene ECEL

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