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A chemical fire has been burning for several days at plastics warehouse just outside of Parkersburg, West Virginia. State officials still don’t know exactly which materials caught on fire at the facility after midnight on Saturday, what the potential health effects will be on residents of this town in the northwestern part of the state, or when the fire will be completely extinguished.

West Virginia Republican Gov. Jim Justice declared a state of emergency on Monday and requested federal aid for firefighting and environmental tests. “We’re trying to source all the professional advice we can source,” he said, “and do the right things for our people.”

Nearly a decade ago, two volunteer firefighters warned that the warehouse, which is owned by Maryland-based Intercontinental Export Import, Inc., was at risk of a major fire. Last February, West Virginia Department of Environmental Protection inspectors said the facility’s general housekeeping was “unsatisfactory” and its materials storage was “marginal.”

After the fire, the West Virginia DEP ordered the company to determine which materials were burning and provide a detailed explanation of how they will be disposed. According officials with the West Virginia Department of Military Affairs and Public Safety, the warehouse may have contained nylon, titanium dioxide, and formaldehyde.

The Mid-Ohio Valley Health Department is warning the 44,000 Parkersburg residents to avoid contact with the smoke and to stay indoors until the smell from the fire is no longer detectable. “If you are experiencing shortness of breath or difficulty breathing, or unusual coughing you should seek medical attention promptly,” the department said in a statement on Thursday. Area schools have been shuttered since Monday.

On Friday, the West Virginia DEP announced that the Environmental Protection Agency would be sending a plane that has the ability to take high-resolution images. The aircraft will be used to identify spots continue to burn.

President Donald Trump has yet to make a statement about the ongoing emergency. He won West Virginia by more than 40 points.