About 30 people attended a rally organized by local environmental groups to protest outside of a conference about metallurgical coal co-sponsored by Norfolk Southern.
When a warning is in effect, industrial facilities in the Mon Valley must limit their activities, and residents, especially vulnerable ones, are discouraged from spending time outdoors.
The federal lawsuit had asked for $42 million fine for U.S. Steel under the Clean Air Act. The fire knocked out pollution controls for more than 100 days.
The fine is for violations at the Clairton Coke Works for the second quarter of 2022. That is in addition to more than $458,000 in fines for the first quarter.
U.S. Steel will begin closing three of its 10 remaining coke batteries at its Clairton plant later this month. It is expected to cut emissions by 15 to 20 percent.
