Methylene chloride is highly toxic. It can cause serious harm through inhalation, skin contact, and ingestion, and at high concentrations it can kill. The chemical, also known as dichloromethane, is so dangerous that the EPA finalized a rule in 2024 banning virtually all consumer uses in the United States. At least 60 deaths have been linked to methylene chloride in paint strippers alone between 1980 and 2018.
How It Harms the Body
What makes methylene chloride especially dangerous is what happens after you breathe it in. Your liver breaks it down and, in the process, converts some of it into carbon monoxide, the same odorless gas that leaks from faulty furnaces. That carbon monoxide binds to your red blood cells and prevents them from carrying oxygen. The result is a form of internal suffocation: your brain and organs are starved of oxygen even though you’re still breathing.
This delayed mechanism is part of what catches people off guard. Someone might finish using a product containing methylene chloride, feel fine initially, and then develop worsening symptoms as the carbon monoxide builds up in their bloodstream over the following hours.
At high concentrations, methylene chloride also disrupts the heart’s electrical rhythm, which is particularly dangerous for anyone with underlying cardiovascular disease. In severe exposure cases, doctors have documented kidney failure, liver damage, and destruction of the tiny tubes inside the kidneys that filter waste from the blood.
Symptoms at Different Exposure Levels
You can smell methylene chloride at roughly 200 parts per million (ppm) in air. At that concentration, about three hours of exposure is enough to noticeably reduce your attention and hand-eye coordination. At around 490 ppm, the vapors can irritate your eyes and damage the surface of the cornea, though these effects typically resolve within a few days.
At 800 ppm, symptoms escalate: dizziness, nausea, tingling or numbness in the fingers and toes, and a feeling of drunkenness. You may lose the ability to stay steady on your feet or perform precise movements. At extremely high concentrations (8,000 to 20,000 ppm), unconsciousness and death become real risks. These fatal exposures most often happen in enclosed spaces with poor ventilation, like bathrooms or basements where someone is stripping paint with the door closed.
Cancer Risk
The International Agency for Research on Cancer classifies methylene chloride as a Group 2B carcinogen, meaning it is “possibly carcinogenic to humans.” The U.S. Department of Health and Human Services has similarly concluded that it may reasonably be anticipated to cause cancer. The evidence is strong enough in animal studies to raise concern, though definitively proving cancer causation in humans requires long-term data that is inherently difficult to collect for chemical exposures.
The 2024 EPA Ban
In May 2024, the EPA issued a final rule under the Toxic Substances Control Act that effectively prohibits methylene chloride for all consumer uses. The rollout is happening in phases. Distribution to retailers was banned as of February 2025. Manufacturing and importing for consumer products ends after May 2025, and processing for consumer use stops after August 2025.
Most industrial and commercial uses face a general prohibition by April 2026, though certain narrow exceptions exist. Commercial refinishing of wooden furniture, decorative pieces, and architectural fixtures with artistic, cultural, or historic value gets an extended deadline of May 2029. Some industrial applications in aircraft and aerospace also receive temporary exemptions. Workplaces that continue using methylene chloride under these exemptions must follow a strict Workplace Chemical Protection Program.
Workplace Exposure Limits
OSHA sets the permissible exposure limit for methylene chloride at 25 ppm averaged over an eight-hour workday, with an action level of 12.5 ppm that triggers monitoring and medical surveillance requirements. The short-term exposure limit is 125 ppm over any 15-minute period. For context, the concentration where people start losing coordination (200 ppm) is already well above both of those thresholds, which gives you a sense of how little margin there is between “allowed” and “harmful.”
Methylene Chloride in Decaffeinated Coffee
One place you might still encounter methylene chloride is in decaffeinated coffee. Some manufacturers use it as a solvent to extract caffeine from coffee beans. The FDA currently allows residues of up to 10 parts per million in roasted decaf coffee and instant decaf. Testing has found at least one brand reaching 8.9 ppm, nearly hitting that ceiling. The amounts involved are vastly smaller than what causes acute toxicity, but the presence of a chemical the EPA has otherwise moved to ban has drawn growing scrutiny.
Protecting Yourself During Exposure
If you still have products containing methylene chloride or work in an industry where it remains in use, ventilation is the single most important protective measure. The fatal cases almost universally involve enclosed spaces. Open windows and doors, use fans to move air, and never work in a room where you can’t maintain a strong cross-breeze.
Standard latex or nitrile gloves offer poor protection. Methylene chloride penetrates most common glove materials quickly. If you need hand protection, double-gloving with polyvinyl acetate or using Viton gloves provides a meaningful chemical barrier. Skin absorption is a real route of exposure, not just inhalation.
Environmental Breakdown
Methylene chloride does not persist in the environment as long as many other industrial chemicals. In air, sunlight and chemical reactions break it down with a half-life of roughly 53 to 127 days. In water, bacteria and chemical reactions degrade it faster, with a half-life of one to six days. Over 90% of the methylene chloride released into the environment eventually converts to carbon dioxide. It is not one of the “forever chemicals” that accumulate indefinitely, but its toxicity at the point of use remains the primary concern.