The company announced that work would resume on Thursday at the second coke battery located at its No. 13 production facility within Mon Valley Works.

The first of three separate explosions occurred at around 10:45 a.m. on August 11. Two separate independent investigations into the incident were launched by Engineering Design and Testing Corp. and the U.S. Chemical Safety and Hazard Investigation Board. The investigations found that the explosions occurred in the transfer area of coke batteries 13 and 14 while workers were opening and closing valves as part of planned maintenance. The Board's report stated that the gas monitoring alarm was activated before the explosion and that workers were instructed to evacuate. The report prepared by the company stated that the explosion occurred as a result of combustible coke oven gas escaping due to damage to an 18-inch cast iron valve.

Coke ovens are defined as large industrial structures consisting of many narrow and long ovens. In these ovens, coal is exposed to high temperatures in an oxygen-free environment to produce coke, which is then used in steel production. Following the explosions in August, the facility was placed in “hot standby” mode, meaning heating was maintained but no coke production took place. U.S. Steel officials said this period was used for repair work and equipment checks.

Amanda Malkowski, senior media relations manager at U.S. Steel, announced that work at the No. 13 production facility would begin on Thursday, with coke production scheduled to resume on Friday. Malkowski stated that the Allegheny County Health Department had been informed of the restart process and that the process would be closely monitored. It was noted that with the battery back online, emission control systems would be active and emissions would be continuously monitored.