CHARLESTON, W.Va. - A state official says he "can guarantee" some West Virginians are breathing in a carcinogen while showering after the chemical spill.

Environmental Quality Board official Scott Simonton says the crude MCHM that spilled into the water supply ultimately can break down into formaldehyde. He says the breakdown can happen in the shower and that formaldehyde is most toxic when inhaled.

He calls respiratory cancer the biggest risk with breathing in the chemical. He made the remarks to a state legislative panel Wednesday.

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Initial testing at Vandalia Grille in Charleston showed traces of the chemical. Other testing showed no traces of formaldehyde, but samples are still being processed.

Freedom Industries' Jan. 9 spill in Charleston spurred a water-use ban for 300,000 West Virginians for days, but officials have lifted it.