Pregnant women living in areas affected by West Virginia's chemical spill are being warned to stick to bottled water, even if their tap water has been declared safe. State health officials issued the advisory late Wednesday night after consulting with the Centers for Disease Control and Prevention. While the CDC had previously determined that levels of the chemical, MCHM, below 1 part per million could be considered safe, the alert advises pregnant women to wait until it has been completely flushed from the water system.
Health officials say the advisory was issued out of "an abundance of caution," likely because so little is known about MCHM and its potential health effects. The CDC has been vague about how it reached the 1 ppm safety level, the Charleston Gazette reports:
Senior CDC press officer Tom Skinner said, "There's not a lot of data that we have with this particular chemical as the letter alludes to. We're basing our calculations on the limited data and experience that we have on this.
"That also involves data from animals and people, so I think that's why the letter is worded the way that it is," Skinner said late Wednesday night.
In his letter to [DHHR Secretary Karen] Bowling, Frieden defended the CDC's methods, noting that "there are few studies on this specialized chemical" and that agency officials "used the available information."
"These calculations use safety factors to take into account the differences between animals and people, and to consider possible effects on specialized populations," Frieden wrote. "An additional safety factor was applied to account for the limited availability of data."
A week after the 7,500 gallons of MCHM were first spilled into the Elk River, over 200,000 of the 300,000 people affected have been given the go-ahead to use their tap water again.