In this final post on my series related to the January 9 chemical spill in West Virgina, I address wrongheaded claims that the spill also exposed Charleston residents to dangerous levels of formaldehyde. A few weeks after the spill, West Virginia Environmental Quality Board Vice Chairman Scott Simonton alleged that final traces of crude MCHM are breaking down and exposing residents to dangerous levels of formaldehyde. “I can guarantee that citizens in this valley are, at least in some instances, breathing formaldehyde,” Simonton told legislators at a public hearing. Simonton said that he found formaldehyde in three water samples from a Charleston, West Virginia, restaurant. But West Virginia's Bureau for Public Health Commissioner Dr. Letitia Tierney called these claims “totally unfounded,” as well as “misleading and irresponsible,” for good reason. As she explained to reporters, Simonton is not part of any official investigation related to the spill, and she cannot validate his tests. In any case, she noted that the MCHM would need to be heated to 500° Fahrenheit before it would break down into formaldehyde. Others have offered similar criticisms of Simonton's assertions. In any case, traces of formaldehyde are not alarming or particularly risky. Humans produce it simply by breathing because it is a byproduct of respiration. It is also released through cooking and is relatively high when one cooks such things as Shiitake mushrooms. Competitive Enterprise Institute Adjunct Scholar Dana Joel Gattuso points out in her study on chemicals and cosmetics that Shiitake mushrooms contain 100-400 parts per million of formaldehyde, some of which is released as a gas when mushrooms are cooked. But no one is sounding alarms about Shiitake mushrooms as a source of formaldehyde! Some studies show that formaldehyde produces relatively mild acute symptoms—such as eye irritation—at about 800 ppb, while others indicate that extra sensitive individuals might experience such effects when exposed to 100 ppb. In comparison, Simonton said he found water in the West Virginia restaurants with levels of 32 and 33 ppb, which is hardly worrisome. Prolonged exposure to relatively high levels of the chemical may have health effects, which is an issue for workers using concentrated amounts of formaldehyde. But it has nothing to do with this chemical spill and any trace levels of formaldehyde found in drinking water.