AUGUSTA, Maine — Firefighters who contract cancer potentially linked to their jobs would be entitled to workers’ compensation benefits under legislation that received preliminary support Thursday in the House. The Senate already has passed the measure.

Both volunteer and professional firefighters are already eligible for workers’ comp if they suffer cardiovascular or lung problems.

On Thursday, the House of Representatives voted 104-40 after lengthy debate in support of a bill that would automatically extend those benefits to veteran firefighters diagnosed with various types of cancer.

Supporters argued the expansion was merited given the toxic stew of airborne chemicals firefighters face when battling blazes in modern homes and buildings.

“These people need to have all of the help that they can,” said Rep. Thomas Wright, D-Berwick.

LD 621 does not guarantee that firefighters will get workers’ comp during their bout with cancer. Officials in charge of workers’ comp can challenge whether the illness may be linked to other factors, such as an unhealthful lifestyle or family history.

But it would make it easier for firefighters to receive workers’ comp by presuming a link between the cancer and exposure to toxic substances while fighting fires.

Ron Green Jr., a Bangor firefighter and 4th District vice president for the Professional Fire Fighters of Maine, said right now people who find themselves in that situation face a difficult choice.

“Do I go to fight the workers’ compensation program to get the benefit, or do I fight to save my life?” Green said after the vote. He and other firefighters have made frequent trips to Augusta to lobby lawmakers in support of the measure.

Lawmakers on the Legislature’s Labor Committee made several significant changes to the bill to address concerns about its scope.

For instance, to be eligible a person must have been an active firefighter for at least five years and regularly responded to calls during that time. The committee also capped the eligibility age at 70 and said the person must have been active with a fire department within the last 10 years. That particular type of cancer must not be prevalent in a person’s family to be eligible for workers’ compensation under the bill.

During spirited debate on the House floor, critics of the bill said they did not question the merit of the proposal. Instead, they suggested that expanding the eligibility for workers’ comp could result in huge expenditures for municipalities and therefore taxpayers.

“It’s certainly difficult to vote against this bill, but I say it is the responsible thing to do,” said Rep. Cynthia Dill, D-Cape Elizabeth.

Rep. Andre Cushing, R-Hampden, suggested that the bill was another potential unfunded mandate from the state that, when combined with pending cuts to state support to municipalities, will effectively force towns to increase property taxes.

But supporters said there is no documented evidence of large increases in workers’ comp expenses in the 29 other states that have adopted similar legislation. Maine and Connecticut are the only New England states that do not extend the benefits to firefighters with cancer.

Rep. Steven Butterfield II, D-Bangor, pointed out that states with large firefighter populations, such as California, have been offering the workers’ comp benefits for years without problems.

“I have voted against things in committee … that I believed in simply because we could not afford it, but this is absolutely not one of them,” said Butterfield.

The bill faces one more vote in the Senate, which already has approved the measure, before being sent to Gov. John Baldacci for consideration.