This morning I heard reports of formaldehyde being found in Charleston, West Virginia water samples as a result of the recent chemical spill there. My first thought, as a chemist, was "You know, that doesn't make any sense". A closer look confirmed that view, and led me to even more dubious things about this news story. Read on - there's some chemistry for a few paragraphs, and then near the end we get to the eyebrow-raising stuff.
The compound that spilled was (4-methylcyclohexane)methanol, abbreviated as 4-MCHM. That's its structure over there.
For the nonchemists in the audience, here's a chance to show how chemical nomenclature works. Those lines represent bonds between atoms, and if the atom isn't labeled with its own letter, it's a carbon (this compound has one one labeled atom, that O for oxygen). These sorts of carbons take four bonds each, and that means that there are a number of hydrogens bonded to them that aren't shown. You'd add one, two, or three hydrogens as needed to each to take each one up to four bonds.
The six-membered ring in the middle is "cyclohexane" in organic chemistry lingo. You'll note two things coming off it, at opposite ends of the ring. The small branch is a methyl group (one carbon), and the other one is a methyl group subsituted with an alcohol (OH). The one-carbon alcohol compound (CH3OH) is methanol, and the rules of chemical naming say that the "methanol-like" part of this structure takes priority, so it's named as a methanol molecule with a ring stuck to its carbon. And that ring has another methyl group, which means that its position needs to be specified. The ring carbon that has the "methanol" gets numbered as #1 (priority again), so the one with the methyl group, counting over, is #4. So this compound's full name is (4-methylcyclohexane)methanol.
I went into that naming detail because it turns out to be important. This spill, needless to say, was a terrible thing that never should have happened. Dumping a huge load of industrial solvent into a river is a crime in both the legal and moral senses of the word. Early indications are that negligence had a role in the accident, which I can easily believe, and if so, I hope that those responsible are prosecuted, both for justice to be served and as a warning to others. Handling industrial chemicals involves a great deal of responsibility, and as a working chemist it pisses me off to see people doing it so poorly. But this accident, like any news story involving any sort of chemistry, also manages to show how little anyone outside the field understands anything about chemicals at all.
I say that because among the many lawsuits being filed, there are some that show (thanks, Chemjobber!) that the lawyers appear to believe that the chemical spill was a mixture of 4-methylcyclohexane and methanol. Not so. This is a misreading of the name, a mistake that a non-chemist might make because the rest of the English language doesn't usually build up nouns the way organic chemistry does. Chemical nomenclature is way too logical and cut-and-dried to be anything like a natural language; you really can draw a complex compound's structure just by reading its name closely enough. This error is a little like deciding that a hairdryer must be a device made partly out of hair.
I'm not exaggerating. The court filing, by the law firm of Thompson and Barney, says explicitly:
30. The combination chemical 4-MCHM is artificially created by combining methylclyclohexane (sic) with methanol.
31. Two component parts of 4-MCHM are methylcyclohexane and methanol which are both known dangerous and toxic chemicals that can cause latent dread disease such as cancer.
Sure thing, guys, just like the two component parts of dogwood trees are dogs and wood. Chemically, this makes no sense whatsoever. Now, it's reasonable to ask if 4-MCHM can chemically degrade to methanol and 4-methylcyclohexane. Without going into too much detail, the answer is "No". You don't get to break carbon-carbon bonds that way, not without a lot of energy. If you ran the chemical (at high temperature) through some sort of catalytic cracking reactor at an oil refinery, you might be able to get something like that to happen (although I'd expect other things as well, probably all at the same time), but otherwise, no. For the same sorts of reasons, you're not going to be able to get formaldehyde out of this compound, either, not without similar conditions. Air and sunlight and water aren't going to do it, and if bacteria and fungi metabolize it, I'd expect things like (4-methylcyclohexane)carboxaldehyde and (4-methylcyclohexane)carboxylic acid, among others. I would not expect them to break off that single-carbon alcohol as formaldehyde.
So where does all this talk of formaldehyde come from? Well, one way that formaldehyde shows up is from oxidation of methanol, as shown in that reaction (this time I've drawn in all the hydrogens). This is, in fact, one of the reasons that methanol is toxic. In the body, it gets oxidized to formaldehyde, and that gets oxidized right away to formic acid, which shuts down an important enzyme. Exposure to formaldehyde itself is a different problem. It's so reactive that most cancers associated with exposure to it are in the upper respiratory tract; it doesn't get any further.
As that methanol oxidation reaction pathway shows, the body actually has ways of dealing with formaldehyde exposure, up to a point. In fact, it's found at low levels (around 20 to 30 nanograms/milliliter) in things like tomatoes and oranges, so we can assume that these exposure levels are easily handled. I am not aware of any environmental regulations on human exposure to orange juice or freshly cut tomatoes. So how much formaldehyde did Dr. Scott Simonton find in his Charleston water sample? Just over 30 nanograms per milliliter. Slightly above the tomato-juice level (27 ng/mL). For reference, the lowest amount that can be detected is about 6 ng/mL. Update: and the amount of formaldehyde in normal human blood is about 1 microgram/mL, which is over thirty times the levels that Simonton says he found in his water samples. This is produced by normal human metabolism (enzymatic removal of methyl groups and other reactions). Everyone has it. And another update: the amount of formaldehyde in normal human saliva can easily be one thousand times that in Simonton's water samples, especially in people who smoke or have cavities. If you went thousands of miles away from this chemical spill, found an untouched wilderness and had one of its natives spit in a collection vial, you'd find a higher concentration of formaldehyde.
But Simonton is a West Virginia water quality official, is he not? Well, not in this capacity. As this story shows, he is being paid in this matter by the law firm of Thompson and Barney to do water analysis. Yes, that's the same law firm that thinks that 4-MCHM is a mixture with methanol in it. And the water sample that he obtained was from the Vandalia Grille in Charleston, the owners of which are defendants in that Thompson and Barney lawsuit that Chemjobber found.
So let me state my opinion: this is a load of crap. The amounts of formaldehyde that Dr. Simonton states he found are within the range of ozonated drinking water as it is, and just above those of fresh tomato juice. These are levels that have never been shown to be harmful in humans. His statements about cancer and other harm coming to West Virginia residents seem to me to be irresponsible fear-mongering. The sort of irresponsible fear-mongering that someone might do if they're being paid by lawyers who don't understand any chemistry and are interested in whipping up as much panic as they can. Just my freely offered opinions. Do your own research and see what you think.
Update: I see that actual West Virginia public health officials agree.
Another update: I've had people point out that the mixture that spilled may have contained up to 1% methanol. But see this comment for why this probably doesn't have any bearing on the formaldehyde issue. Update, Jan 31: Here's the MSDS for the "crude MHCM" that was spilled. The other main constituent (4-methoxymethylcyclohexane)methanol is also unlikely to produce formaldehyde, for the same reasons given above. The fact remains that the levels reported (and sensationalized) by Dr. Simonton are negligible by any standard.