Congress will soon have the chance to acknowledge in a meaningful way an ugly Cold War episode in which our own servicemen were used as guinea pigs.

It should be done.

The House recently passed a measure that would provide free health care for veterans who were involved in secret tests beginning in the 1960s.

SHAD, which stands for Shipboard Hazards and Defense, was part of Project 112, a Cold War chemical warfare initiative.

In it, hundreds of servicemen on tugboats in the Pacific were unknowingly sprayed with chemical and biological agents -- among them nerve gas and an anthrax-like substance.

They were inside sealed quarters when the testing was going on, but many now say the filters designed to protect them didn't always work.

The tests, they say, have caused serious health problems.

Enter Congress.

The Department of Veterans Affairs provides health care to veterans, but it's not free for all veterans -- they must have certain disability ratings linked to illnesses or injuries that are relative to their military service to get free care.

The House bill, a package of veterans legislation, would not require veterans who were involved in the SHAD testing to prove that their health problems are service related to get free health care.

Rep. Denny Rehberg requested earlier this year that the SHAD provision be included in the bill.

After 40 years, it's certainly possible that some of the veterans could have illnesses that aren't related to the experiments. But because the military was conducting experiments on the men that could have endangered their health without their knowledge -- and because the program didn't come to light until the 1990s -- it's unreasonable to make the veterans prove what the results of that experiment were on them individually.

It's better to err on the side of the 500 or veterans involved.

It's better to give them the benefit of the doubt. This isn't the first time legislation to give the SHAD veterans health care has passed in the House, but it has stalled before in the Senate.

It should pass this time and be signed into law. We urge the Montana delegation to cast their votes that way.