In 2016, The Frank R. Lautenberg Chemical Safety for the 21st Century Act amended the Toxic Substances Control Act (TSCA) and created a mandatory requirement for EPA to evaluate existing chemicals using transparent methodology and risk-based assessment. Not simplistic epidemiology.

This was actually a good thing. We want to make sure people are still safe as new data arrive and since they were using science and not statistical correlation, we could have confidence in the results.

Among the first 10 chosen to be re-examined was Dichloromethane, commonly called Methylene chloride, a common industrial solvent and used in the past as a paint stripper but also found in things like automotive cleaners and various other consumer products. It isn't found in nature, it is a chlorinated hydrocarbon often made from methane by substituting chlorine atoms for hydrogen atoms in that gas or wood alcohol.

Methylene chloride

Because it is chemically "simple" there was concern about it being metabolized and animals with high levels of exposure in lab experiments have gotten liver and kidney issues. In humans, there are really only case studies, obviously no one is experimenting on humans and giving them kidney damage.(1) In home use, acute deaths have only occurred after shocking violations of common sense safety precautions, but that doesn't mean long-term exposure using poor ventilation standards might not be a worry.(2) 

Due to known concerns, the Occupational Safety and Health Administration (OSHA) has long had stringent safety controls in place.

Those controls have worked so it is a bit of a surprise that EPA has created a new ban that is using a very accelerated timeline - 15 months. A ban in 15 months on the compound will cut its uses in half, without any increase in worker safety. There have been 85 deaths that have been documented but, and not to be glib about human life, there have been 10 times as many deaths by cow trampling in that time - and EPA does not ban cows.

It is easy for EPA to create bans, watching Administrator Michael Regan's testimony before the Congressional Agricultural Committee yesterday you might think he gets a commission every time he makes statements like 'the courts say we have to ban (insert a chemical here)', but part of their decision-making on a ban should be the societal impact. The economy is already in peril, costs have skyrocketed and the White House is forcing people to buy electric cars when the supply chain has still not recovered from the COVID-19 pandemic. 

Regan says it will be fine in this case, substitutes are available, but he grew up the son of a government employee. He's been in government his whole life. Everything is that simple when you are a government employee because you don't have contracts or revenue or competitors like companies have. Intelligently-run companies have long-term deals to avoid supply chain issues but now they will have to pay for a product they can't use by government fiat while buying another one as well.

EPA has been looking at this compound for a while. Their 2011 report stated “some evidence of carcinogenicity” in male rats and “clear evidence of carcinogenicity” in females but methylene chloride is not a human carcinogen and rats are not little people so it was left in the exploratory pile like almost all animal studies.

Because OSHA standards have worked well the proposed ban comes as a surprise. Should companies really be surprised from this point on? The Biden EPA bans first and discusses later so this may be the new normal. 


(1) The Agency for Toxic Substances and Disease Registry has found trace levels of it in water and ambient air and in 2023(1), even reading that kind of thing alarms people as we have become more removed from science, and more chemophobic, but 'the dose makes the poison', so use instructions have always been clear that you have to keep exposure low. 

(2) Home uses were a concern because people working in homes are sloppy compared to industry. If you used it to strip a bathtub in an unventilated room the risk was substantial. As Dr. Josh Bloom of the American Council on Science and Health said in 2018, "Methylene chloride is arguably the most dangerous of all the solvents sold at Home Depot. Chemists use it all of the time, but we do so in fume hoods. Some argue it's not necessary to ban it, but this is not a knee-jerk chemophobic response by EPA. There is real risk here."

EPA followed our recommendation and banned it for home use like paint thinners in 2019.