Essroc officials said in a statement that it will implement strict dust-control improvements over the next 60 days as part of ongoing environmental efforts, and has already made investments to repair equipment.

Essroc recently agreed to pay a US$38,400 penalty for air-pollution violations, which triggered several complaints last year from nearby residents.

Essroc will be required to perform weekly instead of monthly “visible emission observations” at its South Queen Street plant as part of efforts to prevent future violations, according to a consent order signed by plant director Heinz Knopfel and the West Virginia Division of air quality director William Durham.

The Division of Air Quality officials conducted an inspection of visible emissions at the cement plant between 21 October and 2 November in response to citizen complaints, the order said.

The inspection revealed that dust was coming from near the top of a silo that houses clinker. The investigation also found that seals on the access doors to enter the silo were not sealing properly, allowing dust to escape.

Plans to minimise or eliminate dust-emission sources at the plant are expected to "significantly reduce emissions, as well as help to improve visibility for our workers in the indoor clinker-handling area," Essroc officials said Monday.

The company also said Monday that the facility reached a three-year safety milestone, having passed one million man-work hours without a time-loss accident.