EPA’s just-released methylene chloride draft risk evaluation: Some important context

Richard Denison, Ph.D.is a Lead Senior Scientist.

After more than a month’s delay, EPA today released its draft risk evaluation for methylene chloride.  Running to 725 pages (not counting more than a dozen supplemental files), it will take some time to digest.  But here are some initial observations that provide context for those of you who will be looking closer.

First, methylene chloride is a very nasty chemical.  It has killed a lot of people.  It causes cancer.  Short- and long-term exposure to it is tied to liver effects, immune system effects, nervous system effects, and reproductive/developmental effects.

So it shouldn’t be surprising that EPA’s draft – even coming from an administration not known to be overly worried about the risks of chemicals – has found that most industrial, commercial and consumer uses of methylene chloride present unreasonable risks.

For example, EPA found that workers using methylene chloride-based paint strippers face high risks.  Of course, we knew that already:  EPA identified those risks more than five years ago, and proposed to ban those uses.  This EPA decided it had to do it all over again – which means that thousands of workers have continued to be unnecessarily exposed to this deadly chemical.  And it will be even more years before we get back to where we were before EPA took its mulligan.

So the good news is that EPA seems to be acknowledging that methylene chloride presents high enough risks to warrant regulation under the Toxic Substances Control Act (TSCA).

The bad news is that EPA is dramatically underestimating the magnitude of methylene chloride’s risks – by pulling the same tricks it has for other chemicals among the first 10 it is evaluating under TSCA:

  • EPA once again ignores all exposures and risks to the general population by falsely assuming those exposures and risks are eliminated by actions it has taken or could take under other laws. That means ignoring over 4 million pounds of methylene chloride annually released to air, water and land.  See this backgrounder for the details and why this EPA assumption about methylene chloride is deeply flawed.
  • EPA once again grossly understates risks to workers:
    • EPA assumes that workers will always wear fully effective personal protective equipment (respirators and gloves) to make many of the risks it identifies go away – and to grossly understate the magnitude of the unreasonable risks it does find.
    • EPA once again finds a cancer risk to workers unreasonable only if it exceeds a level of 1 in 10,000 – which is 100 times higher a risk than warrants regulation under TSCA to protect workers and other vulnerable subpopulations.
    • For occupational non-users (ONUs), EPA has once again failed to identify unreasonable risks for the most highly exposed, and hence most vulnerable, workers unless it finds that the majority of workers also face unreasonable risks.

These are just a few initial observations based on our reading of EPA’s opus so far.

So while it’s somewhat encouraging that this new draft risk evaluation has found many more risks than previous drafts, we can already tell the draft falls far short of adequately describing the risks presented by methylene chloride.

Stay tuned.

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