State and federal authorities continue to descend on Charleston, West Virginia in the wake of a devastating chemical spill Thursday that has left 300,000 residents of nine counties unable to drink tap water and has forced the closure of schools and businesses.

President Obama on Friday declared a state of emergency for West Virginia and ordered federal aid to supplement state and local response efforts to the spill, which was first detected on Thursday. The environmental emergency was caused by the leak of an estimated 7,500 gallons of 4-methylcyclohexane methanol (MCHM) from a tank at a Freedom Industries facility along Elk River. Although complaints about foul odors began coming in to the state’s Department of Environmental Protection just after 8 a.m. on Thursday, the company didn’t report the leak until 12:05 p.m.