The old women and young mothers herding sick children gather after sunrise on the brown wooden benches just outside the clinic. At 9 a.m., more than an hour before the doctor's arrival, health aide Vivian Harmer leads the wheezing congregation in prayer.

By the time the doctor finishes his four-hour visit, 40 people have traipsed through the tiny office and examination room. All blamed the fine, gray alumina dust spewed by the Alpart refinery two miles away for their respiratory problems.

Short of breath and, increasingly, of patience, those living near Jamaica's bauxite mines and alumina plants have been brushed off by authorities as isolated complainers, and their claims of ill health as nothing more than anecdotal.

But fresh evidence of a link between emissions and respiratory illness, coupled with a rising militancy among those who say the industry is poisoning its neighbors, has raised the question of what Jamaicans are willing to pay to develop their second-largest industry.

"It's not just the people who are choking to death. Look at my fruit trees! Look at my roof!" said Udel Lloyd, an asthma sufferer, pointing to the rot and rust on her zinc-coated corrugated roof that was new four years ago. Her home flanks the railroad tracks serving Alpart. Sprinkled with the almost invisible dust from boxcars carrying the alumina to nearby Port Kaiser, Lloyd's mango and ackee trees bear misshapen black fruit.

Lloyd, 73, said those living near the refinery despair of getting officials in Kingston, the capital, to deal with the problem.

"That's the Big Man over there," she said, gesturing toward Alpart. "What he want, he get. He make money for the government. Nobody in the government cares about us."

Residents of the bauxite-alumina sites, mostly in these undulating southwestern hills around Mandeville, have complained throughout the industry's half-century of operations that their ailments stem from exposure. Health studies elsewhere have linked bauxite to hypertension and alumina dust to asthma and sinusitis, yet Jamaican authorities dismiss claims of illness.

Officials reject requests for compensation, medical treatment or corrective measures on the grounds that there is no statistical proof of cause from the processing of bauxite into alumina -- the key element for making aluminum.

Complaints from thousands of Jamaicans about asthma, sinusitis and children with birth defects have prompted a militant minority to challenge what they describe as the Caribbean nation's see-no-evil policy. Angry demonstrators have clashed with police and set fire to company trucks.

"We don't think there's a connection -- we know there is," insisted Courtney Gill, a 33-year-old former plant maintenance worker. He has twice placed his 9-year-old son, who suffers from cerebral palsy, in the path of a train to draw attention to the community's problems.

"He don't know what's going on, so he isn't scared," Gill said of the boy, also named Courtney. "I put my Bible on the tracks to mark where I would have to take him off if the train didn't stop, but it did both times."

Most of the asthmatics reject such extreme action but are angry nonetheless.

Even before community concerns escalated to public protest, the claims of illness inflicted by the industry caught the attention of Patrece Charles-Freeman, a medical student at the University of the West Indies. After an exhaustive study of emissions and medical records in a 10-mile radius of the Halse Hall bauxite-alumina operation in neighboring Clarendon parish, Charles-Freeman submitted a doctoral thesis last month documenting dramatically elevated incidence of asthma, sinusitis and allergies among those living close to the mining and refining operations.

In her study of 2,559 people, Charles-Freeman found 37 percent of adults and 21 percent of children living within six miles of the facility suffered sinusitis. Asthma afflicted 23 percent of adults and 26 percent of children. Allergies, likewise, were markedly more prevalent among those who lived closest to the plant than in control groups seven to 10 miles distant.

"The industry needs to investigate the negative effects and implement corrective measures," Charles-Freeman said, outlining the recommendations detailed in her thesis. Until three years ago, the four industrial complexes guided by the Jamaica Bauxite Institute issued periodic checks of about $17 to the most persistent complainers.

While the Ministry of Health provided Charles-Freeman with equipment and staff to conduct her environmental health study, she said the institute and the industrial enterprises that are all part-owned by the government refused to provide her their monitoring data and at times attempted to thwart her investigations.

"Jamalco threatened to cut off water to people if they cooperated with the study," she said of the alumina producer in her study area, an enterprise in which the Jamaican government and Alcoa each own 50 percent.

Jamalco referred inquiries to Alcoa headquarters in Pittsburgh, where spokesman Kevin G. Lowery said no one at the Clarendon plant recalled having contact with Charles-Freeman but that some monitoring data are available in periodic reports made to the government.

Alpart spokesman Lance Neita likewise said air quality data are supplied to the Bauxite Institute but declined to discuss other issues. He said no one at the plant was authorized to discuss operations while ownership changes. The Health Ministry's chief medical officer, Barrington Wint, said the bauxite-alumina industry hazards have gone unstudied because of scarce funds and more urgent priorities.

Those officially charged with ensuring that bauxite mining and alumina refining are conducted safely contend there is no reliable evidence that exposure to alumina dust is harmful.

They attribute the claims of illness to economic motivations.

"We have long recognized that when the so-called environmental lobby came in, most of the problems had nothing to do with the environment. They are social and economic problems," said Parris Lyew-Ayee, managing director of the Jamaica Bauxite Institute, responsible for keeping Jamaica competitive in the world alumina market as well as protecting the environment.

Jamaica is the only major bauxite source where the mines are in populated areas, said Lyew-Ayee, noting that the deposits in Australia, the biggest producer, are in the outback.

Neither the mining nor the processing of bauxite into alumina is very labor-intensive, so the operations provide few jobs for the surrounding communities of farmers. Although the $773 million industry is Jamaica's most lucrative after tourism, it employs fewer than 5,000 people across the country.

He disparaged Charles-Freeman's research as unreliable because it covered only a small area. He dismissed claims of roof damage from dust as the fault of inferior materials. As for crop failures and stunted fruit growth, he said plants sown by the industry on reclaimed land prosper and that the problems elsewhere are "not from alumina dust -- any dust can cause that."

Lyew-Ayee also denied any conflict of interest in his institute's joint responsibilities for exploiting the resource and setting environmental standards.