The wives of some chemical workers at an Exxon refinery in Louisiana appear to face five times the usual risk of having miscarriages or stillborn babies, according to a study commissioned by the company.

Environmental Health Associates (EHA) of Berkeley, Calif., informed Exxon of its findings nearly 10 months ago. EHA said data was too limited to permit "firm conclusions," but that statistical evidence showed an association between a woman's pregnancy problems and her husband's exposure to the company's waste-water treatment plant, where water is cleansed of a variety of chemicals that result from petroleum processing.

In several groups at the plant, the rate of miscarriage and stillbirth jumped from about 4 percent before workers were exposed to the area with the chemicals to about 20 percent after exposure, said Dr. Robert W. Morgan.

An Exxon announcement Thursday night confirmed the study results but said the study's authors wrote that the findings "are not conclusive" and that the "findings further suggest that any effect on the sperm of employes would be temporary."

Exxon turned down a plan by Environmental Health Associates to continue the study. An Exxon spokesman said the company will monitor the situation, and expects to start a program "in the very near future." A spokesman said it is expected "to take several years to develop enough data to reach any conclusion."

Virtually every refinery in the United States has a waste-treatment system similar to the one where the study on miscarriage and stillbirth was undertaken.

EHA has asked Exxon for permission to publish the study, but Exxon spokesman Richard Lee said yesterday, "We are not giving out copies . . . . I do not believe there is any intention to publish it."

The study was ordered by Exxon after workers in the waste-treatment area of the refinery complained about the high rate of miscarriages their wives were experiencing. In the waste-treatment area workers are exposed to chemicals contaminating the water from the processing of gasoline, oil, waxes and lubricants.

Before the study began, an Exxon spokesman said, the company responded to worker complaints and installed a new vent system and better "housekeeping" procedures. He said Exxon also offered protective clothing and respirator masks to employes.

For the EHA study Morgan interviewed and took medical histories from 89 women who had 210 pregnancies. Of those, about 22, or 10.5 percent, resulted in miscarriages or stillbirths.

Though there are no good statistics on what number of miscarriages might be expected in this group, Morgan said that as many as 10 percent would seem normal, if it were not for another striking aspect of the numbers:

He found that the rate of miscarriages before the workers were exposed to the waste-treatment job area was only about 4 percent. He said low rates of miscarriage tend to be correlated with socioeconomic status: the lower the status, the higher the rates of miscarriage. The Exxon workers, he said, are generally well-educated and financially well-off.

But after the husbands started work in the waste-treatment area, Morgan said, the rate of miscarriages increased to 20 percent, five times as high, among wives of electricians, mechanics and instrument workers.

In that group, Morgan said, there were 97 pregnancies and four miscarriages before exposure to the work area. After exposure there were 35 pregnancies and seven miscarriages. Among electricians and instrument workers alone there was an eightfold increase after the men started working in the waste area.

Electricians, mechanics and instrument workers have the highest exposure to the waste-treatment process in the Exxon facility. Among all workers involved in waste treatment, including those without high or regular exposure, the number of failed pregnancies increased slightly more than twofold, according to Morgan's report.

Little is known about what chemicals might cause a change in the sex cells of men, Morgan said, so that "if there is an effect here, we just don't know which of the many chemicals might have caused it."

He said it is likely that the problem would occur if sperm cells were damaged genetically as they were being made by the body. If the defective sperm cells fertilized an egg, the result might be an embryo with such abnormal genes that growth to term would become impossible.

Morgan said in a telephone interview that because so little is known about the relation between chemicals and miscarriage, or about miscarriage rates in general, the striking numbers in the study "have some biological credibility, though the study is not conclusive. It is very important to do more work."

The Occupational Safety and Health Administration earlier this month took samples at the plant to determine what chemicals were present and whether employes were exposed to harmful levels of them. The results of the investigation were not available.

Exxon's Baton Rouge refinery, the second largest in the United States, produces gasoline, asphalt, diesel, jet fuel, waxes, lubricants and LPG propane.