A thick, dark gray haze blanketed Bahrain Monday as smoke from torched Kuwaiti oil wells blew south, and residents worried that the pall would cause health problems.

Some people have been telephoning environmental agencies to complain of headaches and nausea, but there were conflicting statements from officials on whether the haze was a health hazard.Allied military officials say Iraqi troops set almost 200 oil wells on fire to further ravage Kuwait. The Iraqis blame the blazes on allied bombings.

Texas companies stood by to extinguish the fires once the war ends. One expert said the number of burning wells amounted to an unprecedented disaster in the industry that would take months to extinguish.

Bahrain is 220 miles south of Kuwait. Rain in the arid region usually is welcome, but Dr. Mahmoud al-Attal, an adviser with the Health Ministry, said any wet weather now would only cause more problems.

"The danger lies in its turning into acid rain, which would affect buildings," he said.

However, he told residents in a newspaper statement that only people who were ill would suffer from the thick black smoke, which carried the stench of petroleum.

U.S. Ambassador Charles Hostler told Americans not to worry about the gray cloud cover and said it was not harmful to breathe.

But Walter Vreeland, a consultant at Bahrain's Environmental Protection Committee, said people who are outside for prolonged periods of time - especially asthmatics - should place a handkerchief or other protection over the mouth and nose.

"It's probably harmful in the long term," said Vreeland. "This could go on for months if the wells keep burning and the wind comes out of the northwest, as it usually does."

Khaled Fakhro, the environmental committee's vice chairman, said he had asked environmental agencies in the United States and France for more information about this type of air pollution.

Qatar, about 20 miles south of Bahrain, reported reduced atmospheric visibility in Doha because of the pollution.

Farther south, officials in the United Arab Emirates told residents the black smoke and awful stench generally would not affect people's health.

Firefighter Red Adair of Houston said Sunday each well fire will take four to five days to extinguish. But his top firefighter Monday said he could not estimate exactly how long it would take to extinguish the blazes until firefighters can get to the scene.

"It'll definitely be the most wells anybody's attempted to work on at a time," said Raymond Henry, vice president and senior firefighter of Red Adair Co. Inc.

Henry said the biggest job he can remember was five burning oil wells in Libya that took the Adair company weeks to put out during the 1960s.