The Continuing Attack on Methylene Chloride Paint Strippers

The Continuing Attack on Methylene Chloride Paint Strippers


In the June, 2017 issue of Popular Woodworking (#232) I wrote about the efforts of the EPA to eliminate paint and coating removers that contain methylene chloride or N-Methylpyrrolidone (NMP) from the consumer market. I recounted how this effort had been going on for more than 25 years and is based on the unsubstantiated claims that exposure to methylene chloride can cause cancer and the fairly well substantiated claims that exposure to NMP can lead to reproductive problems in pregnant women.

This effort by the EPA continues. But in the meantime, there’s been an interesting turn of events. Now it’s consumer advocacy groups pressuring retail suppliers to stop selling these strippers. And these groups have apparently succeeded with Lowe’s, Home Depot and Sherwin-Williams. Each of these chains has announced that it’s ceasing to sell these categories of strippers. The reason given isn’t that they cause cancer, but that a number of people have died while using methylene chloride strippers to strip bathtubs in a closed bathroom. The EPA estimates 40 deaths since 1975. The Center for Public Integrity estimates 56 deaths since 1980. This comes to between one and two deaths per year depending on which figures you use.

Neither non-methylene chloride or N-Methylpyrrolidone contain methylene chloride or N-Methylpyrrolidone (NMP), but both contain more than 50% water, which can cause problems on old furniture.

In response to both the EPA and retail store chains, manufacturers are putting warnings on their cans against using the stripper on bathtubs. The warning on this can is in the lower right corner. It says, “Do not use to strip bathtubs.” There’s a drawing of a bathtub with a red line through it.

The cause that’s usually given is the victim putting his or her head down into the bathtub while working. Methylene chloride fumes are heavier than air, so doing this increases exposure significantly over what might have built up in the room. Methylene chloride metabolizes to carbon monoxide in the blood, which replaces oxygen and can lead to a heart attack, especially in people with heart problems.

You should never use a methylene chloride stripper (or any solvent, for that matter) without good air movement, in one door or window and out another, or outside. Assuming these chain stores go through with their intentions, it’ll leave just one category of effective strippers available: those that are highly flammable.

The Story of W.M. Barr

It used to be that furniture stripping was done with flammable solvents or by scraping off the coating. The scraping was done with pieces of glass, not with the modern steel card scrapers we use today. The scraping damaged the wood surface.

In 1946 a fellow named William M. Barr invented a new paint stripper based on the non-flammable solvent, methylene chloride. It quickly took off in the marketplace because it was such a huge advance over the flammable solvents. This advance was probably the biggest ever made in paint strippers. At least, I can’t think of others that are equivalent.

(Methylene chloride is also an exempt VOC, so it’s more environmentally friendly than the flammable solvents. This wasn’t an issue in 1946.)

The success of this stripper led Barr to start a company that still exists today, W.M. Barr & Company. The brand name you might associate most with this company is Klean-Strip.

Consumer Advocacy Groups

The consumer advocacy groups seem to be led by Safer Chemicals Healthy Families, which claims to be a coalition of 450 organizations comprising 11 million members. Apparently, they wrote letters to the chain stores asking them to stop selling strippers containing methylene chloride or NMP and that was enough to be successful with these three big retail chains. I guess the chains reasoned that these strippers weren’t big enough profit makers to be willing to upset a large number of their customers.

Sherwin-Williams issued the following statement: “Our customers are our #1 priority at Sherwin- Williams, so we’re eliminating methylene chloride paint strippers from our stores. We have several effective alternatives available to serve your project needs.” Sherwin-Williams doesn’t carry strippers based on NMP. I’d assume that Lowe’s and Home Depot would say something similar.

My Opinion

These stores carry all sorts of dangerous stuff. I’ll just point to one: ladders. Three hundred people a year are killed in falls from ladders. 164,000 go to emergency rooms. Remember that only 1.5 people die a year from acute exposure to methylene chloride. And though every life is valuable, these figures undercut the reasoning.

If Sherwin-Williams were really making my needs their #1 priority, they’d let me choose what to use, maybe with an instruction to not use for stripping bathtubs. (Some suppliers are doing that now.) Contrary to their claim, there aren’t any equivalent alternatives. As I’ve pointed out previously, all are either highly flammable, or they are weak and contain a lot of water. Leaving these strippers on the wood for the time it takes them to work can lift veneer.

Very old furniture and woodwork were typically finished with either shellac or lacquer, which don’t require the strongest strippers to remove. But over the last several decades professional refinishing shops have increasingly replaced these finishes with high-performance catalyzed lacquers and varnishes because of their increased durability. These finishes are also common on newer furniture and woodwork.

To test for shellac or lacquer, dab some alcohol or lacquer thinner on the finish. Alcohol will remove shellac, which was widely used before the 1920s, and lacquer thinner will remove lacquer, which was widely used since the 1920s.

It’s easy to strip a shellac finish using alcohol, which, so far, isn’t being regulated. Lacquer thinner is being regulated in some parts of the country, however, and is being formulated with large amounts of VOC-exempt acetone, which evaporates rapidly.

So, when these coatings start deteriorating, as all do, and need to be replaced, the only available products that’ll remove them may be lye, (which is destructive to the wood and joints and dangerous to work with), flammable strippers and sandpaper, which is destructive to patina and wood decoration, such as carvings, fretwork and turnings.

Concerning flammability, this is a real issue. I haven’t found any statistics, but I have had direct experience. A number of years ago one of my furniture restoration clients hired a painter to strip the paint from the wood trim and paneling in several rooms of a very nice house. After applying the flammable stripper to a section of one room, the painter flipped on a light switch, which sparked and started a fire that couldn’t be extinguished before half the house had been destroyed. What to do? Until the EPA acts further, methylene chloride and NMP strippers should continue to be available at independent paint stores. They’re not likely to bow to the pressure from these advocacy groups.


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