(Bloomberg) -- A wall holding back almost a million gallons of toxic, flammable liquids collapsed Friday at the site of a Houston-area chemical disaster.

Nearby industrial sites and a state war memorial were warned to take cover. Workers at Intercontinental Terminals Co.’s storage facility in the suburb of Deer Park were in the process of pumping chemicals into another tank. Earlier, Brent Weber, the executive overseeing the recovery work, told reporters the threat of a benzene release would be heightened during the process.

ITC is working to determine the precise contents of the spill, an ITC official said by phone. The U.S. Coast Guard closed a portion of the nearby Houston Ship Channel.

The U.S. Chemical Safety Board announced late Thursday it will be investigating the blaze. The Texas National Guard dispatched troops to assist local authorities with air monitoring.

On Friday, the lone monitor detecting benzene was on the northeast side of Deer Park, the working class suburb near the Houston Ship Channel that’s home to ITC’s tank farm. The U.S. Environmental Protection Agency, one of four entities conducting air tests, said its own monitors hadn’t registered any signs of benzene on Friday. EPA representative Adam Adams said he couldn’t explain the discrepancy.

--With assistance from Kevin Crowley and David Wethe.

To contact the reporters on this story: Joe Carroll in Houston at jcarroll8@bloomberg.net;Rachel Adams-Heard in Houston at radamsheard@bloomberg.net

To contact the editors responsible for this story: David Marino at dmarino4@bloomberg.net, Mike Jeffers

©2019 Bloomberg L.P.