A pulp mill in Washington state where 11 workers died after a chemical tank collapsed in May had a history of safety complaints, poor maintenance and discharges of toxic chemicals, records reviewed by The Associated Press show. This was reported by Qazaqyia.kz citing Associated Press.

State inspectors had planned to visit the plant to interview workers about two unrelated safety complaints the week of the tragedy, one of the deadliest U.S. workplace accidents in decades. Those plans were disrupted when the tank failed as the workday began, expelling huge amounts of a caustic liquid capable of causing severe burns.

The AP reviewed state and federal records involving inspections and safety complaints at the Nippon Dynawave Packaging Co.'s plant in Longview, Washington. Prior to the accident, the state Department of Ecology had issued 54 environmental violation notices against the company since 2016 and fined them $41,500 for eight serious violations.

The state's Department of Labor and Industries investigated more than a dozen safety complaints at the plant since 2018 and issued almost $7,000 in fines for violations. Its investigation into the tank collapse is ongoing, and it has opened two new investigations since May.

More than $2.4 million in workers' compensation claims have been paid for 169 employees injured on the job since 2015, the agency reported, including for injuries related to exposure to caustic substances. The mill, which employs 530 workers, produces pulp that is made into paper goods.

The multiple equipment failures and safety violations are a "red flag" for this company, said Stephen Kmiotek, a chemical engineering professor at the Worcester Polytechnic Institute who has closely followed the fatal accident and its aftermath.

"My impression, you put it all together, including the most recent tank collapse, is it is a site that has not been maintained, and that creates risk to employees and risk to public," he said.

The U.S. Chemical and Safety Board released a report last week saying the company knew the tank was "not fit for continued service" months before the failure, but they still used it. The state's Department of Ecology filed a violation notice against the company after the accident, listing 35 citations.