On Friday, August 22nd, a massive explosion at the Smitty’s Supply petrochemical plant in Roseland, Louisiana, U.S. forced the evacuation of a nearby elementary school and all residents within a one-mile (1.6 km) radius.

More than two weeks after the initial event, local residents are still understandably concerned about the soot, ash, and debris from the thick column of black smoke from the refinery fire, much of which appears to still be coating their homes, yards, roads, and nearby waterways.

“The Environmental Protection Agency (EPA) has confirmed toxic substances were found in soot,” as reported by local news station FOX 8. “According to a report … investigators detected arsenic, barium, chromium, lead and other hazardous materials in two samples collected the day after the explosion.”

Journalists with The Lens have reported further on the potential scale of broader environmental contamination: “According to a map released by the EPA, the river was impacted as far as 47 miles downstream. Residents, however, shared photos on social media that appeared to show sheen beyond that limit, at the mouth of the Tangipahoa where it empties into the lake.”

Government agencies and contracted emergency responders have deployed at least 6,000 feet (1.8 km) of containment booms – a type of emergency barrier designed to help curb the spread of pollution – in nearby waterways, but toxicologists are still warning people in the impacted communities about possible risks of exposure.

Adam Mahoney with Capital B News adds: “Regional EPA officials are telling people to wash the soot off any outside surfaces of their homes and to wash their hands if they come into contact with it, but there are still no definitive answers on what chemicals are contained in the black, oily sludge streaked across residents’ properties.”