CHARLESTON, W.Va. (AP) — When federal officials decided what chemical levels West Virginians could safely consume in water tainted by a January spill, their standard assumed people would be exposed for two weeks, not 100-plus days.

Months later, Centers for Disease Control and Protection officials see no reason to adjust a chemical benchmark they quickly created off limited lab rat research. However, a local health official argues the CDC needs to account for ongoing chemical exposure, even if it’s minimal.