In many parts of the Third World, illiterate farmers pour drinking water into empty pesticide containers and work without protective clothing in fields that have been sprayed with deadly insecticides.

The result, according to some scholars, is a health problem of near epidemic proportions. Between 1.5 million and 2 million persons in developing countries are poisoned every year from exposure to pesticides, and pesticide-related deaths are estimated at 10,000 annually, according to United Nations figures.

"I would say this is probably the single most important long-term health threat in the developing world," said Robert Wasserstrom, a senior associate of the World Resources Institute. "There's a tremendous accumulation of these biocides in the environment. It's not like the stuff disappears or washes away."

The abuse of deadly pesticides -- many of them manufactured and exported by U.S. multinational companies -- is one dimension in a broad debate over U.S. corporate behavior that has been raised in the wake of last month's disaster at Bhopal, India, where more than 2,000 people died from a poison gas leak at a Union Carbide Corp. plant.

Environmental critics long have faulted multinational companies for exporting production processes or potentially hazardous products such as pesticides and pharmaceuticals to countries that lack the knowledge or bureaucratic infrastructure to regulate them properly. Although the causes of the Bhopal incident are still unknown, critics have questioned the wisdom of Union Carbide's placement of such a dangerous plant on the outskirts of a highly populated area -- a siting decision that probably would not be permitted here.

Leading American exporters of pesticides such as Monsanto Corp., E. I. duPont de Nemours & Co. and Dow Chemical Co. say they make every effort to assure that recipient nations are aware of the potential dangers from improper use of their products. Now, however, some industry officials question whether more needs to be done.

"Bhopal has tended to say to people that we need to be a little more responsible," said Ronald Lang, executive director of the Synthetic Organic Chemical Manufacturers Association. "It's going to be increasingly important that people abroad understand what the risks of these products are. . . . I think you're going to see more of a willingness on the chemical industry's part to help come up with a proposal that's workable."

How far these proposals go is likely to be the subject of intense debate, however. Until now, the chemical industry and other U.S. business groups have railed against the "regulatory imperialism" and "international nannyism" of environmentalists and consumer groups that want to impose U.S. safety standards on other countries.

The Pharmaceutical Manufacturers Association, for example, has declared as a top priority for the new session of Congress a bill that would allow U.S. firms to export drugs that have not been approved for sale in this country. PMA President Joseph Stetler calls this a "jobs bill," contending that it would stop the flow of manufacturing plants to Europe, where U.S. drug companies have taken advantage of more streamlined regulatory procedures to manufacture and market new drugs.

"We're really not trying to foster some unsafe product on an unsuspecting overseas public," Stetler said. "Some of these countries have pretty sophisticated standards of their own."

Yet consumer groups question drug regulation in even the most advanced nations. In 1982, for example, Merck & Co. Inc. of Rahway, N. J., began marketing in Britain, West Germany, Sweden and four other countries a new arthritic drug called osmosin that had been manufactured by the company in Britain and had not been approved by the U.S. Food and Drug Administration.

Within a year, the company suspended distribution of the drug worldwide after it was linked to adverse medical reactions in Britain, a Merck spokesman acknowledged. Dr. Sidney Wolfe, the director of Ralph Nader's Health Research Group, says osmosin was associated with at least 38 deaths and more than 400 adverse reactions. "There's a lot of things that go on in other countries that we don't have any control over," Wolfe said.

In yet another arena where the export issue has been fought out, the National Association of Manufacturers last year endorsed a proposal before the Consumer Product Safety Commission that would have permitted U.S. firms to export products that had been banned by the agency for domestic sale.

The chief proponent of this plan was CPSC Commissioner Terrence M. Scanlon -- recently sworn in as the agency's new chairman -- who argued that it was not up to "unelected regulators" in the United States to dictate to foreign nations what products can be sold within their borders. But consumer groups mounted a successful lobbying campaign to defeat the plan, charging that it would open the way for hazardous chain saws, lawn mowers, hair dryers and other products to be shipped overseas.

"People were up in arms over the prospect that these products would be able to be dumped abroad," said Commissioner Stuart M. Statler, who joined a 3-to-1 commission majority opposing the Scanlon proposal.

The outcome of some of these battles has long-range implications for the U.S. economy, some economists and industry spokesmen say. Some of the industries most affected by proposals to control exports -- such as chemicals and pharmaceuticals -- operate in highly competitive global markets. The fear is that restrictions on exports, or even greater efforts at information-sharing with developing countries, would handicap U.S. companies to the benefit of unfettered foreign competitors, industry officials say.

The $12.8-billion-a-year world pesticide market, for example, is dominated by such European firms as Bayer (West Germany) and Ciba-Geigy (Switzerland) with only two U.S. companies -- Du Pont and Monsanto -- among the top six exporters. If U.S. companies are prohibited from selling certain pesticides abroad -- or if they must disclose more information about the dangers of those pesticides than their competitors -- they could well lose those overseas markets to the Europeans, industry officials say.

"If you carry this process too far, you put my members at an economic disadvantage," said Jack Early, president of the National Agricultural Chemicals Association. "My companies are going to have to compete with pesticides coming out of Germany and Japan, where they don't have any regulations. It's proper to notify and share information, but don't put shackles on my people."

So far, that argument has proved persuasive with Reagan administration officials. In his last few days in office, President Carter signed a sweeping executive order that would have sharply restricted the export of products that either had been banned by U.S. regulatory agencies or whose use had been restricted. It also would have required that detailed warnings be submitted to the recipient nations concerning the hazards of particular products.

It turned out to be what one former Carter administration official calls "the shortest executive order in the history of the Republic." In one of its first deregulatory moves just a few weeks after it took office, the Reagan administration revoked the order and instructed the State Department to conduct a new study of the issue. It has remained at State ever since.

"That was one of those 'midnight regulations' that went out in the closing days of the old administration when everyone's sleeping," said James Tozzi, the former deputy administrator of the Office of Management and Budget, who was instrumental in killing the order. "The issue was that there are only two or three sectors in the export market that make any money for this country and one of them is chemicals. . . . That order was cumbersome, and it could lead to our products being discriminated against."

That philosophy has since been adopted by the administration at the United Nations, where there have been attempts to establish an international policy on the issue. Three weeks ago, the United States was the only country to dissent when the United Nations General Assembly voted 147 to 1 to continue publishing and to expand a worldwide directory of dangerous products that have been banned or restricted in 60 countries.

The idea behind the directory is to help many developing countries evaluate what restrictions should be placed on the use of products being shipped within their borders. For the most part, experts say the problem is not that chemical companies manufacture pesticides that are banned in advanced nations and then export them to the Third World. Rather, it is the misuse of pesticides by poverty-stricken and isolated Third World farmers -- a problem that could be ameliorated by the distribution of more information to Third World governments, they say.

But U.S. chemical and pharmaceutical manufacturers had lobbied the State Department for more than two years to oppose the directory, arguing that their products would get inserted into the directory only because the United States has higher health and safety standards than other countries.

Last April 24, the Chemical Manufacturers Association sent a four-page letter to the State Department arguing that "the listing of U.S. manufacturers and U.S. brand names on the U.N. Secretariat's List will give rise to a negative presumption against such chemicals manufactured in the United States."

"There was a fear among some businesses that, if the U.S. volunteered a lot of information on products for the lists, someone would misuse the lists , especially if other companies in foreign countries did not submit the same information," said State Department spokesman Neal Boyer. "It would end up being discriminatory. . . . There are non-scientists and non-technically-skilled people at the U.N. who are putting them in the document."

Environmentalists, however, insist that the United States should assume the responsibility as a world leader on the issue. "The fact of the matter is we've got to bite the bullet on this one," said Jay Feldman, national coordinator of the National Coalition Against the Misuse of Pesticides. "We as a civilized nation must make a clear determination on what type of standards we set."