An Explosion in Texas Shows the Hidden Dangers of Tanks Holding Heavy Fuels Industry experts believe that changes in the makeup of asphalt and No. 6 fuel oil products stored in heated tanks across the country could pose a risk to workers and nearby communities. This article was produced in collaboration with Berkeley Journalism’s Investigative Reporting Program. Justin Chambers arrived at the U.S. Polyco plant in Ennis, Texas, on the morning of April 23, 2018, with a job to do. One of the asphalt tanks at the plant had been damaged and needed to be demolished, and the 32-year-old foreman was part of a five-man crew of contractors charged with getting it done.