NEW YORK (MarketWatch) — West Virginia authorities knew last year that potentially hazardous chemicals were stored near a vital water supply that’s now been contaminated for four days, but it’s not clear what was done with the information, The Wall Street Journal reported Sunday.

It wasn’t immediately apparent whether authorities had shared the information with the company that runs the water-treatment plant affected by Thursday’s chemical spill, which has left as many as 300,000 people in the Charleston, W.Va., area without clean water.

Putnam County residents get water from an emergency distribution center in Poca, W.V. Saturday. Reuters

That company, West Virginia American Water Co., previously said it was caught off guard by the hazardous chemical that appeared in the water supply on Thursday. But that chemical used to clean coal, known as MCMH or 4-methylcyclohexane methanol, was listed in an inventory document filed with the West Virginia Division of Homeland Security and Emergency Management by Freedom Industries Inc. The chemical reportedly overflowed a containment area around a tank run by Freedom Industries, about a mile upriver from the West Virginia American Water plant.

Meanwhile, frustration is growing among West Virginians who have gone more than three days without tap water, but it could take several more days before authorities determine the water is safe to drink, according to other media reports on Sunday.

Orders not to use tap water for much other than flushing toilets mean that the spill is an emergency not just for the residents and the environment, but for hotels, restaurants and other local businesses, according to the Associated Press. The AP reported seven flights were canceled at Charleston’s Yeager Airport because hotels weren’t meeting a level of service required in agreements between airlines and unions for flight crews and pilots.

Tests of the region’s water on Saturday showed that contamination levels have started to drop. But a West Virginia American Water Co. official said it might take days to provide enough samples to determine whether the water is safe, according to a New York Times report.