In this July 9, 2014, file photo, workers wearing protective clothing and footwear inspect a valve at the "C" tank farm on the Hanford Nuclear Reservation near Richland, Wash. The state attorney general is taking legal action Thursday, July 21, 2016, to protect workers who are exposed to chemical vapors on the Hanford Nuclear Reservation.

  In this July 9, 2014, file photo, workers wearing protective clothing and footwear inspect a valve at the “C” tank farm on the Hanford Nuclear Reservation near Richland, Wash. The state attorney general is taking legal action Thursday, July 21, 2016, to protect workers who are exposed to chemical vapors on the Hanford Nuclear Reservation.

Ted S. Warren/AP

Washington’s attorney general and others are asking a federal judge to immediately take steps to protect Hanford Nuclear Reservation workers from exposure to chemical vapors.

More than 50 workers have received medical evaluations after reporting exposure to vapors in recent months.

On Thursday, Attorney General Bob Ferguson, along with the watchdog group Hanford Challenge, filed motions for a preliminary injunction in federal court in Eastern Washington. The injunction seeks to implement workers protections now, instead of waiting for the outcome of a trial.

The state filed a lawsuit against the federal government over Hanford worker safety last September. Trial is set for next May.

Hanford for decades made plutonium for nuclear weapons, and the site is now engaged in a massive cleanup of the resulting radioactive wastes.