Washington state is suing the federal government again over cleanup at the Hanford Nuclear Reservation — this time over the danger posed to workers by vapor releases from underground waste-storage tanks.

In a federal lawsuit filed in Spokane on Wednesday, state Attorney General Bob Ferguson said the U.S. Department of Energy has known about vapors sickening workers at the site since at least the late 1980s, but hasn't fixed it — even though agencies have issued 19 reports on the problem. Hanford, on the Columbia River in eastern Washington, produced plutonium for nuclear weapons from 1943 to 1987.

There were more than 50 reports of workers being exposed to vapors between January 2014 and April 2015, Ferguson said, and hundreds over the past few decades, with victims suffering from symptoms that include nosebleeds, brain damage and permanent loss of lung capacity. One longtime worker, Gary Sall, died from brain swelling linked to chemical vapors in 2011.

"Neither the Department of Energy nor its contractors have followed through to finally fix the problem and keep our workers safe," Ferguson told a news conference. "If you visited Hanford today, you'd find some workers at the tank farms still exposed to vapors seeping out of these tanks."

The lawsuit also names the Energy Department's contractor at Hanford, Washington River Protection Solutions, as a defendant. An advocacy group for Hanford workers, Hanford Challenge, and a union representing some of them, United Association of Steamfitters and Plumbers Local 598, filed a companion lawsuit.

In statements Wednesday, the department and its contractor said steps have already been taken to improve worker safety at the site, such as by increasing the use of self-contained breathing devices in areas of potential vapor exposure.

"The Department's top priority is the protection of our workforce, the public and the environment," Energy spokeswoman Carrie Meyer said in an email.

Washington River Protection Solutions said that since it took over as the contractor for tank operations in 2008, it has increased and improved sampling methods for detecting vapors and created wider vapor control zones for workers, and it's working on a multiyear plan to improve monitoring for vapors, among other things.

Washington sued the Energy Department in 2008 over the glacial pace of cleanup at Hanford, and the federal government agreed to a timeline for cleanup in a 2010 settlement. It's lagging in meeting those goals.

The Energy Department already asked for a one-year extension of its deadline for emptying nine leak-prone tanks, saying that having more employees wear respirators was slowing down the work.

Some 56 million gallons of toxic waste — much of it radioactive — is stored in 177 underground tanks on the 586-square-mile reservation. Most of the tanks are single-shelled and considered inadequate, and workers have been transferring the waste inside them to double-shelled tanks. The tanks are vented to keep dangerous gases from building up inside and causing explosions. While the vents do have filters that capture toxic particulates, the filters don't capture chemical vapors.

Current and former Hanford workers who attended Ferguson's news conference described a patchwork of safety practices that lead to some people carrying full breathing apparatus — like the air tanks firefighters carry into a burning building — while others nearby have no protection.

Pete Nicacio, business manager for Local 598, scoffed at Hanford's use of a rope delineating where workers need to wear breathing gear and where they don't, saying workers call it "the magic rope." He said his union members insist on breathing gear, and as a result, bosses have sometimes taken work away from them.

Tom Carpenter, executive director of Hanford Challenge, said a major problem is that Hanford doesn't have monitoring systems sophisticated enough to know what gases workers have been exposed to — some of which are dangerous enough to cause health problems at infinitesimally low concentrations. More than 1,500 chemical gases have been found in the tanks, and doctors are often forced to try to figure out which ones workers might have been exposed to based only on their symptoms.

Diana Gegg, 64, was working as a heavy equipment operator at Hanford one day in 2007 when she smelled something like chlorine or ammonia. She became dizzy and developed "flu-like symptoms which never went away and still haven't," as well as a bad stutter and memory problems.

After the news conference, she handed a reporter a typed statement because of her difficulty speaking.

Another worker, electrician Steve Lewis, said he has experienced inflamed skin and continual congestion in his throat. But, he added, "I've watched other people deal with things that were way worse than that."