The Delaware Department of Natural Resources and Environmental Control reported the release of more than 1,600 pounds of sulfur dioxide from the Delaware City Refining Co.
The refinery is owned by PBF Energy.
According to DNREC, a problem in the scrubber control system led to the release of the sulfur dioxide, which is considered to be a hazardous substance by the Environmental Protection Agency.
The release occurred at 4:52 p.m. on Monday.
The release is now being investigated by DNREC. The department can levy fines.
Sulfur dioxide is a byproduct of the refining process.
