Hurricane Harvey caused dioxin, one of the most potent human carcinogens, to leak from the San Jacinto Waste Pits, posing a threat to fish and public health, the U.S. Environmental Protection Agency has confirmed.
High levels of dioxin were detected in a sample of river sediment collected from the site by an EPA dive team, the agency said. Preliminary analysis of the sample, one of 14 collected from the site, found dioxin at concentrations 2,000 times higher than the level at which the EPA requires cleanup.
The pits, used for decades to store waste from a paper mill, are among 13 Superfund sites hammered by Harvey. It is one of Houston's most dangerous Superfund sites and one of the most vulnerable to storms. The pits lie along the Interstate 10 bridge that crosses the San Jacinto River just east of Houston and were entirely submerged for days at the height of Harvey's flooding.
Hundreds of families in riverfront neighborhoods east of Houston have been complaining for the past month that massive flooding around the pits poisoned the river, likely fouled their land and contaminated wells with sewage, industrial pollution and toxic sediment. One local resident shot a drone video that he said showed damage to a cap covering a portion of the waste pits.
The EPA has now confirmed, based on the presence of dioxin in the sample, that the protective cap was damaged and that waste material leaked out. Previously, spokesmen for the EPA and one of the companies overseeing the cleanup of the site had said there appeared to be no rupture.
Additional testing will be required to determine the extent of the contamination, the EPA said. The agency said it had ordered the companies, International Paper and Industrial Maintenance Corp., to take "immediate action" to repair the cap.
The pits were capped in 2011 as a temporary measure. EPA Administrator Scott Pruitt promised recently to announce a decision in October on a plan to permanently remove the waste from the river.