Reuters reports that the House of Representatives' coronavirus subcommittee asked JBS USA, Tyson Foods Inc and Smithfield Foods Inc to provide records of inspections, complaints and other internal documents.

The panel also asked the Occupational Safety and Health Administration (OSHA), the nation's workplace safety watchdog, to provide records of its efforts to enforce worker safety rules.

Meatpacking plants emerged as early hubs of coronavirus infection last spring, forcing many of them to close temporarily and pushing up meat prices. Companies erected physical barriers and took other steps to protect workers, but they were not able to eliminate the risk of infection.

Then-President Donald Trump in April ordered meat processing plants to stay open to protect the US food supply, despite concerns about coronavirus outbreaks.

Surrounding communities also were affected. Meatpacking plants were associated with at least 236,000 coronavirus cases and up to 5,200 deaths as of July, according to the National Academy of Sciences.

Labour unions and workers have accused the companies of taking inadequate steps to protect workers.

Smithfield, Tyson and JBS said they have spent hundreds of millions of dollars on worker safety, bonuses and other measures. All three companies said they would cooperate with the investigation.

The Meat Institute trade group said case rates for industry workers were five times lower in December than they were in May, while infections rose for the US population as a whole.

The coronavirus subcommittee's chairman, US Representative James Clyburn, said his panel would also examine OSHA's enforcement efforts under Trump, which he described as ineffective.

"It is imperative that the previous Administration’s shortcomings are swiftly identified and rectified to save lives in the months before coronavirus vaccinations are available for all Americans," he said in a statement.

In response, OSHA said more stringent safety guidelines issued to employers on Friday were a "first step" in its efforts to work with Congress on worker protections.

A Reuters investigation found that workplace inspections by OSHA dropped 44 percent between March, when the virus began to spread widely in the United States, and December.

OSHA last year fined Smithfield, owned by Hong Kong-listed WH Group Ltd, $13,494 for a violation at its Sioux Falls, South Dakota, plant, where four workers died and nearly 1,300 were infected. The agency fined JBS $15,615 for a violation at its Greeley, Colorado, plant, where six died and about 300 tested positive. Both companies are appealing the fines.

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