Despite evidence that there is profit in the practice, a private research group reported yesterday that organic chemical plants have managed to shave only a small fraction off the hazardous wastes they generate each year.

INFORM, a nonprofit research organization based in New York, said its three-year examination of 29 plants in three states found some "remarkable examples" of waste reduction, but not enough to make more than a tiny dent in the billions of pounds of toxic wastes generated annually by the organic chemical industry.

The report's conclusions were questioned by a spokesman for the Chemical Manufacturers Association, who said an industry study that is expected to be released this week found that 725 chemical plants and allied industries reduced waste by nearly 22 percent from 1983 to 1984.

"Obviously there are two overriding reasons for the reduction," association spokesman Jeffrey Van said.

"One is economic and the other is social," he said. "Our industry, rightly or wrongly, is identified in the public eye as the source of past problems of waste disposal."

There are more than 1,000 organic chemical plants in the United States, and they generate more than 60 percent of the nation's toxic wastes, according to government estimates.

INFORM's report, entitled "Cutting Chemical Wastes," said fewer than half of the 29 plants it surveyed had taken steps to curb waste, from substituting nontoxic chemicals for hazardous ones to altering storage, loading and operating practices.

"Although we could document a reduction of at least 7 million pounds, these plants annually produce billions of pounds of hazardous wastes," said Warren Muir, one of the authors of the report.

Five of the plants that instituted waste-reduction measures saved more than $800,000 as a result, according to the study, which said the savings could be much higher.

"Many companies do not document the full impact of their waste-reduction practices," Muir said.

Among the savers, according to the report, was the Borden Chemical Co. in Fremont, Calif., which cut the volume of phenol-contaminated waste water more than 90 percent by changing the rinsing procedure for its reactor vessels. The company is saving nearly $50,000 a year in disposal costs and is reusing much of the phenol it formerly rinsed away.

The study found that government regulation had little impact on waste-reduction measures, citing an Exxon plant in Linden, N.J., as the only company in the survey that reduced its waste in response to a government directive. To reduce toxic emissions, the plant installed floating roofs on tanks containing volatile chemicals and saved more than $200,000 worth of the easily evaporated materials in a year, according to the study.

The survey found that operational costs, public scrutiny, concern over liability and the "indirect" impact of more stringent toxic-disposal laws were more likely to be the deciding factors in waste-reduction efforts.

Sixteen of the companies included in the survey, including Du Pont, Shell, American Cyanamid, Chevron and most of the smaller firms, declined to cooperate with INFORM researchers, Muir said.

The group compiled information on those companies through government files.

The INFORM study was limited to organic chemical plants in three states, California, Ohio and New Jersey, which contain 23 percent of the industry and differ widely in their regulatory restrictions.

According to Van, the manufacturers' association study included inorganic chemical plants as well as plastic and resin-fabricating facilities.