Chemical Spill in Charleston, West Virginia
The name MCHM or "4-methycycloheaxe methanol" (as newspapers reported it) is not entirely a systematic name and is a little ambiguous. The actual compound is better called  4-methylcyclohexylmethanol and the structure is shown below:

Specific details about its toxicity are not easy to find, though it has been patented as an air freshener ingredient. It has also been around for a long time and is used in the coal industry as a frothing agent in significant quantities so if it had some particularly nasty property we would probably know by now. Some safety information is available (pdf) on the related 1,4-cyclohexanedimethanol and that isn't particularly toxic. So there doesn't seem to be any strong reason to worry about it, though it will taint the flavour of water. There are no obvious paths for it to known nasties in low concentrations in water, so the biggest worry is probably the taint.

Having said all this, the company should not have let it get into the water supply.