Whether it’s airplane exhaust, toxic mold or a nearby polluted stream that is making residents of a city apartment complex sick, the state Bureau of Health intends to find out what’s going on at Griffin Park.

The Bangor apartment complex first made news last spring when state Department of Environmental Protection officials found that plane de-icer from the nearby Bangor International Airport and Air National Guard base was polluting Birch Stream.

The small tributary of Kenduskeag Stream runs through Griffin Park, which is a cluster of two-story apartment buildings totaling 50 units.

Residents complained of nausea, headaches and sinus problems, and they believed that their symptoms were linked to the odor rising from the polluted stream.

“We want to know if it’s safe to live here, and that we’re not poisoning our children every day that we stay at Griffin Park,” said Ann Birmingham, a resident who has served as a spokeswoman for her neighbors, in a statement released this week.

To that end, state toxicologists recently held a series of meetings at Griffin Park, organized by a group of residents who call themselves G.P. Cats.

“I think we’re all working together, trying to find out what’s going on,” Birmingham said in a Wednesday interview, adding that she is hopeful about the process.

While G.P. Cats has long called for a health study, residents did not want the city of Bangor leading such an effort, she said. Residents accuse the city of not sufficiently informing Griffin Park residents of known pollution problems and have said they would have more faith in a health study conducted by a third party.

Andy Smith, state toxicologist, has taken on the role of leading the Griffin Park investigation, using federal bioterrorism funds as well as the resources of his bureau and the city, which has offered to cover the cost of printing and similar services.

While the meetings thus far have been private because of the sensitive nature of the medical information being discussed, representatives from the Toxics Action Center, a Portland-based environmental and public health organization, are “watchdogging” the process, the group’s director, Maggie Drummond, said Wednesday.

“Right now, the most important thing for us is to find out what the residents are breathing,” Drummond said.

But identifying any environmental problem at Griffin Park is a tremendous challenge, Smith said Thursday. As countless cancer studies have shown, the presence of contaminants alone is no smoking gun. It may not be possible ever to pinpoint what caused health problems in the past, Smith said.

“We have virtually no information about what people’s actual exposure is,” he said. “There’s a big difference between what’s in the stream and what people are actually exposed to.”

Complicating the situation is the relatively small number of people living in the 50 apartments at Griffin Park. Because of the human body’s natural variations, most epidemiological studies involve hundreds or even thousands of individuals, Smith said.

But Smith believes that the state can provide Griffin Park residents with some peace of mind.

He and his staff continue to work with residents to design a study of current conditions at Griffin Park, which could include anecdotal information gleaned from interviews with residents, as well as quantitative tests of the neighborhood’s air quality.

“We’re asking, ‘What could be done to give them the comfort that their environment is not a contaminated one?'” Smith said.