"It came up with naphthalene and heavy metals in that. We're waiting on other analysis for dioxins and furans, which are very dangerous toxins," attorney Kevin Thompson said during a meeting attended by 150 local residents.
Thompson added that the residue sample has been sent off for further analysis.
Arkema, which operates the beleaguered plant, claims the smoke and ash that filled the air during the series of fires was not toxic.
After Hurricane Harvey hit, authorities evacuated a 1.5-mile radius around the plant while they waited for the containers to combust, which they said was inevitable.
The chemical plant has lost power and refrigeration capabilities due to Harvey and its aftermath, causing organic peroxides stored in containers at the facility to become unstable and break down as they were exposed to the Texas heat.
Arkema gave notice of the lifted evacuation order early Monday morning after consulting with officials monitoring the scene. The residents were advised to use protective clothing and drink bottled water until further notice.
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