It started four years ago with a small group of residents and workers pushing for answers regarding illnesses and pollution in and around the former IBM plant in Endicott.

It has progressed into a proposal for the largest federal study ever looking at cancer rates among workers in the circuit board assembly industry.

Where it goes from here depends largely on the community's will to pursue it.

Last week, a delegation of 10 scientists and officials from a collection of federal and state agencies met with about 30 residents gathered around folding chairs and tables in the basement of The First United Methodist Church in Endicott.

The citizens group, called the Western Broome Environmental Stakeholders Coalition, has been meeting there monthly for years, pondering why so many community members -- including many former IBM workers -- are developing chronic illnesses, and pushing federal and state scientists for answers.

Taking their leads from these sessions, scientists from the state Department of Health, as well as the federal Agency for Toxic Substances and Disease Registry, have analyzed exposure risks from pollution in the ground, water and air in neighborhoods flanking the sprawling micro-electronics plant at the center of the community.

To date, they have been unable to connect those exposure risks -- which they found to be low -- to a spike in testicular and kidney cancers and certain birth defects found in polluted areas of the community. But based on information gleaned from studies elsewhere in the country, TCE exposure remains a primary suspect.

And the work goes on.

While scientists have pushed ahead with various studies in the community, the plant itself, where millions of pounds of trichloroethylene and other chemicals were stored and used, has been off limits.

That changed last week, when officials from the National Institute of Occupational Safety and Health told residents they believe they can gain access to personnel and industrial hygiene records that will tell them whether the cancer rate is disproportionately high for 28,000 people who worked at the plant on North Street since the 1960s.

Access to the IBM records, coupled with state cancer registries and national death data, would provide the raw materials for the largest NIOSH study of cancer rates in the circuit board industry, said Lynne Pinkerton, an official with NIOSH.

While community members have until May 28 to comment on the proposal, the initial response was positive. Residents who spoke at the meeting and others interviewed since were in favor of the plan. Rep. Maurice D. Hinchey, a member of the federal Appropriations Committee, said he would work to secure funding, and Sen. Hillary Rodham Clinton also said she would support the plan.

Now it's time to stop and think carefully. Pieces to a large and complicated puzzle have been laid on the Southern Tier's doorstep. There is local and national interest in the safety of workers and residents exposed to industrial solvents used extensively in the electronics industry. That includes TCE, which has become iconic of a national debate about public safety in the chemical age.

But residents must understand that NIOSH scientists proposing the IBM cancer study have little expectation that it will yield any meaningful or lasting contributions to their understanding of risks from chemical exposure.

This is why.

Over the course of five decades, the process for circuit board assembly has changed radically, as have the type and quantities of chemicals used. What workers were exposed to in the 1970s is different than what they were exposed to in the 1990s or last year.

About 20 chemicals -- including vinyl chloride, benzene and formaldehyde -- used some time or another in the plant's history are already listed as known cancer risks, according to information in the NIOSH report detailing the feasibility of an IBM cancer study.

About 24 more are listed as suspected or possible cancer risks.

Even if the study showed IBM-Endicott workers suffered disproportionately from cancer -- undoubtedly no small thing -- it is not set up to hone in on any one chemical.

And linking specific chemicals with illness is the kind of science necessary for reform.

"This (study) is mainly to address community concerns," Pinkerton said. "Even if it gives us information about cancer and circuit board manufacturing, it may or not be relevant (to researchers)."

But that doesn't mean it is not worth doing, or that it could not be improved during the public comment period that ends May 28.

While the chemical mix in the workplace has changed over the decades, there remains one constant as far as the community is concerned: TCE.

As evidence supporting its toxicity mounted, TCE was phased out as a production chemical at the Endicott plant.

But its legacy remains, literally rooted within the community. Unlike some other toxic chemicals, such as formaldehyde, TCE does not break down in water and it is difficult to effectively extract from the ground. Relatively high concentrations -- likely spilled from manufacturing process over the decades -- remain under the plant and parts of the village.

Moreover, the exact toxicity of TCE -- used liberally for decades in industry ranging from defense to dry cleaning -- is the center of a national debate, and there is incentive for scientists to find opportunities to document its effects on humans in the interest of future public health policy.

Types of cancers found elevated in the community may provide clues about TCE risks if they are found excessively among workers most likely exposed to the chemical when it was in vogue at the plant.

Dr. Joseph LaDou, a clinical professor of occupational medicine at the University of California at San Francisco, pointed out the importance of also tracking birth defects among the children of IBM employees -- something not included in the initial proposal.

Studies have shown an association with heart defects in particular -- like the ones found in inexplicably high numbers in polluted sections of the village -- and TCE exposure.

Pinkerton said it may be feasible to hone in on the effects of TCE exposure at IBM if the community is interested in that, and to also track birth defects among plant employees.

"What we need to know is, will this study (as proposed) answer their questions. Or do they have other questions?"

Based on standards set by the federal Occupational Safety and Health Administration, IBM can legally expose workers in industrial settings to chemical concentrations, including TCE, that would be unacceptable elsewhere.

Many will reasonably argue that OSHA standards lag far behind current knowledge of chemical exposure.

"They are not health based, but industry compatible," LaDou said. "That means they are not designed to protect workers but to keep industry competitive."

LaDou said he is skeptical that a NIOSH study would find anything critical of current manufacturing practices, because of political pressure and the industrial lobby. But the proposed IBM study might be different, he added, because it involves an industry -- circuit board assembly -- with declining economic influence as it moves offshore.

His advice to the community: "You'll want to stick with it. It is quite likely they will come away with some interesting positive findings."

Richard Clapp, an environmental health professor at Boston University and a research colleague of LaDou's, agreed.

"This whole (circuit board) industry is understudied," Clapp said. "This could be a big deal."

The work of Clapp, supported by LaDou, has shown greater likelihood of IBM employees in the semi-conductor industry dying from certain cancers. It has been challenged by IBM, which maintains that company policy ensures a safe workplace and cites a company-funded study showing cancer among workers no greater, and in some cases lower, than the rest of the population.

If there is a breakthrough in Endicott, it is not likely to come soon. If the proposed NIOSH study gets funding, it will be in the 2008 federal budget. And it could take years, rather than months, to complete.

The residents assembling monthly in the church basement -- largely responsible for work that has brought researchers to this threshold -- still have many unanswered questions after four years.

It's a good bet they have the endurance necessary to pursue answers.