President Trump has signed an order designating meat processing plants as “critical,” paving the way for them to stay open and overriding state restrictions.

Trump signed the executive order April 28 under the Defense Production Act, a Korean War-era law that allows presidents to designate plants and other infrastructure as critical. The order directs U.S. Agriculture Secretary Sonny Perdue to take all necessary steps to keep the plants open, and allows him to do so with other supply chain operations. An administration official told the Wall Street Journal that the Labor Department will protect plant owners from liability in cases of worker illness.

The meat industry has been hit particularly hard by the coronavirus crisis, with some 20 plants being closed at one time or another. Hundreds of workers have been infected by the virus, and about 20 have died from COVID-19.

The meat supply has been severely disrupted. In the week ending April 25, beef production was down 24.5% from the same week last year, pork was down 14.6%, and chicken down 8.2%. Industry leaders have warned of long-term shortages if the situation is allowed to continue.

Trump’s action came under harsh criticism from unios and other worker advocates, with one of them telling the Journal, “We only wish that this administration cared as much about the lives of working people as it does about meat, pork and poultry products.”