An advisory from the Centers for Disease Control and Prevention (CDC) to the West Virginia Department of Health and Human Resources recommends that pregnant women in the area affected by last week’s chemical spill not use tap water until there is no detectable MCHM is in the water.
On January 9, MCMH (4-methylcyclohexane methanol), a chemical used in coal processing, spilled into the Elk River in Charleston, resulting in a ban on the use of tap water for 300,000 people in nine counties in and around Charleston. The CDC letter, made available by the Charleston Daily Mail, explains how the CDC arrived at the 1 ppm “protective level” of MCMH.
This chemical – and its possible adverse effects on human health – was largely unknown to public health officials before the spill. CDC director Dr. Thomas Frieden writes, “there are few studies on this specialized chemical … the only available studies looked at the effects of exposure on animals. Therefore, scientists used the available information about 4-methylcyclohexanemethanol MCHM to calculate how much MCHM a person could likely ingest without resulting in adverse health effects. These calculations use safety factors to take into account the differences between animals and people, and to consider possible effects on special populations. An additional safety factor was applied to account for the limited availability of data. Based on these safety factors and the available research studies, scientists recommended a screening level of l part per million (l ppm) of MCHM in drinking water.” “[D]ue to limited availability of data, and out of an abundance of caution, you may wish to consider an alternative drinking water source for pregnant women until the chemical is at non-detectable levels in the water distribution system,” the letter continues.
The Charleston Daily Mail also made available a Frequently Asked Questions sheet, addressing possible concerns for pregnant and breastfeeding women. National Public Radio (NPR) reports that many residents remain wary of the water supply and say they plan to continue using bottled water for drinking and cooking until MCMH is no longer detectable.