A flaring incident was reported on Wednesday morning at Delaware City Refining Co.
The Delaware Department of Natural Resources and Environmental Control reported the release via the Delaware Environmental Release Notification System.
DNREC reported the release of 100 pounds of sulfur dioxide into the air during the incident. The gas from the refining process is considered to be hazardous by the Environmental Protection Agency.
The refinery was restored to normal operation following the flaring.
The release is currently under investigation by DNREC.