PROVIDENCE — A major statewide terrorism drill meant to train firefighters, police officers and medical crews to save lives after a chemical disaster could be severely curtailed because the Providence firefighters union plans to picket.

The labor action, which the union president downplays as an “informational demonstration” for disability benefits, is stopping dozens of firefighters from other municipalities from participating in Sunday’s drill.

This is the latest in a protracted contract battle between the Providence firefighters and the city. When asked how he could justify disrupting a complicated multi-agency drill, union president Paul A. Doughty said: “How can we take care of you if you won’t take care of us?”

The homeland security drill has been planned for six months and is being financed by a $50,000 federal grant. The scenario is a terrorist attack at the Rhode Island Convention Center that leaves hundreds of victims, requires 40 ambulances, and mobilizes seven hospitals to help.

Rhode Island saw a disaster of that magnitude with The Station nightclub fire, when 100 people died and another 200 were injured. First-responders from different agencies worked together rescuing people. Lives were saved, but there were challenges, such as hospitals surprised by an influx of patients and rescue workers whose radios were incompatible.

Rhode Island has never performed a drill like this, said Leo Messier, the executive director of the Providence Emergency Management Agency. This involves multiple agencies, plus specialized teams for hazardous materials and decontamination, and the National Guard’s civil-support team. Chiefs from various departments will command the scene together. Hospitals will practice decontaminating numerous patients quickly. And a new statewide radio system allowing all agencies to talk to each other will be tested.

Other fire departments can’t spare their on-duty staff to attend the drill, so the grant is paying for overtime for those who volunteer to work. But the fire chiefs can’t order their firefighters to cross a union picket line in another city, so firefighters in other departments and in the statewide teams yesterday began bowing out.

Their loss is a huge blow to the drill, which organizers say will have to be drastically scaled down to make up for having few, if any, ambulances and rescuers. “It’s shocking to contemplate that a union for a public safety agency would attempt to sabotage a preparedness drill,” Messier said. “You’re affecting things that could possibly save people’s lives, for a contract dispute.”

While the Providence police have said they’ll be at the drill, no Providence firefighters have signed up. Even the private ambulance services want to back out, Messier said.

The Providence fire chief said he’s determined the drill will go on — even if they have to scale it down. “We get millions of dollars in homeland security. We’re required to train,” Providence Fire Chief George S. Farrell said yesterday. “I think it’s unconscionable that the officers of Local 799 — if something like this were to happen tomorrow — would put the lives of people on the Fire Department and the lives of people who could be at the Convention Center in jeopardy.”

The union demonstration is over three Providence firefighters with disability claims for cancer. Doughty accused the chief of not backing accidental-disability pensions for those firefighters, which would give them 66 2/3 percent of salary, tax-free. An ordinary disability pension is 45 percent of salary, taxable. Disabled firefighters also get back all the money they’ve contributed to the city’s pension fund — with interest.

Farrell, who disclosed this week that he has leukemia, said he’s been in talks with the mayor for months about this issue. He said he told the city to table the firefighters’ requests for ordinary disability because he believes they can come up with a solution for firefighters with cancer.

But contracts for several firefighters unions have language saying that they will not cross any job action in another city, except for an emergency. So, if the firefighters show up for the drill and find a union protest, they’ll leave.

They’ll still want to be paid for showing up — and the federal grant isn’t going to pay them if they don’t work the drill. That means that their municipalities will have to pay overtime, at a minimum of four hours. Overtime for Providence firefighters is $35.99 an hour, $39.45 for lieutenants, and $42.86 for captains. The drill is expected to last five hours. After hearing from the state association yesterday, the firefighters unions in Pawtucket, Cranston and East Providence canceled, and others are expected to follow.

“If there’s any kind of job action there, the members are going to respect that,” said Pawtucket Fire Chief Timothy McLaughlin. “I’m not going to put my firefighters in the middle.”

He had planned to send six firefighters, a battalion chief, and a mass-casualty vehicle to the drill. “You always get something out of it,” McLaughlin said. “With Providence being the capital city and being neighbors, we get the experience of working together.”

Doughty was dismissive about the drill. “This is more for strategic issues than tactical issues,” he said. “Getting into the [hazardous-materials] suits, sampling the air, it’s stuff we’ve done before.”

Said Messier: “For him to dismiss it, saying this is something you’ve done before… that’s ludicrous. Once you’ve done something once, you don’t have to practice again, you’re done? That’s an asinine thing to say.”

amilkovi@projo.com