Philadelphia residents are advised to drink bottled water “out of caution” until further notice after more than 8,000 gallons of hazardous chemicals spilled into a tributary of the Delaware River in Bucks County Friday night.

While no contaminations have been detected in Philadelphia’s water system “we cannot be 100% certain there will not be traces of these chemicals in the tap water throughout the entire afternoon,” Mike Carroll, deputy managing director for the city’s Office of Transportation, Infrastructure, and Sustainability, said at a press conference Sunday morning.

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The Water Department issued a map for residents to look up whether they are potentially impacted. The map shows that just around all of Northwest Philadelphia and all neighborhoods west of the Schuylkill are not impacted.

More than 8,000 gallons of a latex-finishing solution spilled into the water just before midnight on March 24, according to the Philadelphia Water Department and Office of Emergency Management. However, the cause of the spill is not clear yet.

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Altuglas, a subsidiary of Trinseo PLS, said an equipment failure at their production unit in Bristol, led to a release that spilled into a storm sewer that flowed into Otter Creek, a tributary of the Delaware River. The company employs 110 people and no one was harmed in the release.

The release of material has been stopped and our efforts are now focused on testing the local waterways. We are grateful for the fast response and professionalism of our local first responders, as well as the efforts of the U.S. EPA, the Pennsylvania DEP, and the United States Coast Guard,” Trinseo CEO Frank Bozich said.

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The chemicals released into the Delaware river include butyl acrylate, a flammable liquid used to make paints, coatings, caulks, sealants, and adhesives. Two other chemicals that spilled include Etherl acrylate and methyl methacrylate, both are used in the manufacture of plastics and coatings like later paint.

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The Delaware River is the source of drinking water for millions of residents of Pennsylvania, New Jersey, and Delaware. The bottled water advisory applies only to residents of Philadelphia who live east of the Schuylkill River.