Indonesian police are investigating reports that a local subsidiary of the U.S.-based mining company, Newmont, has polluted a river with mercury and arsenic, poisoning the local population.

Environmentalists accuse the mining company, Newmont Minahasa Raya, of releasing dangerous levels of mercury and arsenic from a gold mine it operates in the north of the Indonesian island of Sulawesi.

They say that over the last eight years at least 30 people have died from symptoms that mirror Minamata disease, caused by mercury poisoning.

Newmont denies the charges, saying its operations conform to both Indonesian and U.S. environmental standards. It says all contaminants have been removed from any waste the company puts into the Ratatotok River and Buyat Bay.

Richard Ness, the head of Newmont Minahasa Raya, says the company does not use mercury in its operations in Sulawesi and he questions the accusations.

"It's not true that NMR's operations have affected the quality of water or the health of the villagers," he said. "Our own children and our employees live in that area, they attend schools. We eat the same fish and shrimp from those waters, and we are not going to expose our employees or the villagers or communities to any unsafe or environmentally unsound practices."

Mr. Ness says the company's monitoring of the water has not shown any rise in the levels of heavy metals.

But, Indonesian doctors in the area say that tests on people living around Buyat Bay show high levels of heavy metals and arsenic in their blood and hair.

Indonesian physician, Dr. Rignolda has done extensive work with local villagers and was instrumental in bringing public attention to the problem.

"I found data in the village that four people already died with indications like feeling very hot in their body before they were dying. And, also skin disease that's very common in the village," he said. "Other health problems in the village are they have a very bad headache and some of the people have no feeling, they lose control over part of their bodies."

Mercury is particularly harmful to unborn children, where it can cause severe mental damage. In older victims it can cause peripheral sensory loss, tremors, hearing and visual deficiencies and in cases of prolonged exposure, death.