The Environmental Protection Agency said it recovered 517 containers of "unidentified, potentially hazardous material" from highly contaminated toxic waste sites in Texas that flooded last month during Hurricane Harvey.
The agency has not provided details about which Superfund sites the material came from, why the contaminants at issue have not been identified and whether there's a threat to human health, the Associated Press reported.
The one-sentence disclosure about the containers was made Friday night deep within a media release from the Federal Emergency Management Agency summarizing the government's response to the devastating storm, the AP said.
At least seven Superfund sites in and around Houston were flooded in the days after Harvey's record-shattering rains stopped.
The AP said it surveyed the flooded sites by boat, vehicle and on foot. The EPA said at the time that its personnel had been unable to reach the sites, although they surveyed the locations using aerial photos.
The U.S. government also received reports of three spills at the U.S. Oil Recovery Superfund site, a former petroleum waste processing plant outside Houston contaminated with a dangerous brew of cancer-causing chemicals.
Records the AP obtained from the Coast Guard showed workers at the site called a federal hot line to report spills of unidentified materials in unknown amounts.
Local pollution control officials photographed three large tanks used to store potentially hazardous waste completely underwater on Aug. 29. The EPA later said there was no evidence that nearby Vince Bayou had been affected.
PRP Group, the company formed to clean up the U.S. Oil Recovery site, said it does not know how much material leaked from the tanks, soaking into the soil or flowing into the bayou.
As part of the post-storm cleanup, workers have vacuumed up 63 truckloads of potentially contaminated storm water, totaling about 315,000 gallons.