DALLAS (AP) — The Environmental Protection Agency is ordering companies responsible for cleaning up a Houston Superfund site flooded during Hurricane Harvey to immediately address damage to a protective cap and subsequent high levels of waste material detected in a sediment sample from the site.

The EPA said Thursday night a sample collected by an agency dive team at the San Jacinto River Waste Pits Superfund site showed dioxins at 70,000 nanograms per kilogram. The EPA level for cleaning is 30 nanograms per kilogram.

The agency says International Paper and Industrial Maintenance Corp., the potentially responsible parties for the cleanup, need to conduct additional tests to ensure any dioxin waste is isolated. The EPA says initial repairs already have been made to the damaged area where protective rock was missing.