Sulfur

Sulfur Dioxide (SO2) has the “struck match” odor and Hydrogen Sulfide (H2S) is the “rotten egg” odor

US Steel Coke plant is a major producer of Hydrogen sulfide Coke is used to produce iron and steel. Clairton’s 10 coke batteries contain 708 coke ovens and more than 6,300 potential emissions points. Each year, the facility produces about 4.3 million tons of coke.

Click here for info on the plant and what you can do when you smell a sulfur or rotten egg odor

Related article
https://www.post-gazette.com/news/environment/2019/02/05/US-Steel-sulfur-dioxide-high-level-recorded-Clairton-Coke-Works-Mon-Valley-Pittsburgh/stories/201902050123