The Delaware Department of Natural Resources and Environmental Control has penalized the owners of the Sunoco plant in Claymont. The agency learned that the company modified an emergency flare without a permit to combust gas from other sources in a "non-emergency capacity."

Sunoco Partners Marketing & Terminals, LP will pay a $600,000 cash penalty and an additional $150,000 towards an environmental improvement project. In addition, DNREC has ordered the company to decommission the flare by March 31, 2019.

Sunoco plans to build a new flare in Pennsylvania.

The $150,000 fine will go towards the transition of Delaware's ambient monitoring network for air pollution from filter-based PM2.5 (particulate) monitoring to continuous monitors located throughout the state.