The State Department is developing a series of sweeping regulations to block any exports -- from heavy-duty trucks to advanced computers -- that could be used in clandestine nuclear, missile or chemical- and biological-warfare programs, according to Bush administration and business sources.

The proposals have set off a firestorm of opposition from business groups and officials within the administration.

Opponents argue that the imposition of unilateral restrictions will undermine more effective U.S. efforts to develop an international regime to stop weapons proliferation.

The curbs would affect exports only from U.S. companies, although a State Department official said he hoped other industrialized nations in Europe and Asia would join in.

The proposals have been under study for 15 months, but they appear to have taken on a new urgency after Iraq's Aug. 2 invasion of Kuwait and reports of massive shipments of U.S. and other Western technology to Baghdad since 1985, administration officials said.

The new rules would require companies to get licenses before shipping anything on a broad list of products to as many as 50 countries, largely in the Third World, that are suspected of running secret programs to make nuclear bombs, the missiles to deliver them and chemical or biological weapons.

While the list of countries has not yet been made public, it would likely include U.S. adversaries such as Libya and Iraq, friendly nations such as India and Pakistan, and allies such as Israel and South Korea.

An administration official said the curbs could affect as much as $250 billion worth of U.S. exports. And if a company ignores the curbs, penalties could run as high as a $1 million fine, 10 years in jail and a 10-year ban on its exports, industry and government sources said.

The State Department proposals raise tensions over exports between business and government that appeared to have abated with the end of the Cold War and an administration decision to support greatly relaxed restrictions on the sale of high-technology products to the Soviet Union and its former Communist allies.

This time, the tensions have taken a different turn, with proliferation of weapons among Third World nations replacing East-West confrontation as the focus.

The issue came front and center with the Iraqi invasion and Baghdad's threat of using poison gas delivered by homemade missiles against American troops. At the same time, the administration must decide whether to continue aid to Pakistan in the face of new information that it is pressing forward with its nuclear weapon program.

"Everyone is running scared to death because of Iraq," said an administration official familiar with the plan. "Some think if they take a series of unilateral gestures it will deflect congressional pressure and show the press we are doing things."

Iraq is known to have been trying to build nuclear weapons and their delivery systems for more than a decade and to have used poison gas both on rebellious Kurds and on Iran. A number of Western nations nevertheless have sold a wide array of sensitive technology to the Saddam Hussein regime.

The United States has approved the shipment of $1.5 billion worth of high-tech products to Iraq since 1985. These sales, which included computers for its nuclear agency and for use in reading satellite intelligence photos, were approved under Reagan and Bush administration policies to favor Baghdad in its war with Iran.

Government records made available to The Washington Post showed that the shipments had the approval of the Defense, State, Energy and Commerce departments and the intelligence agencies.

A State Department official said the sweeping new curbs, being pushed by Richard A. Clarke, assistant secretary of state and director of the Bureau of Political-Military Affairs, have "total support within the State Department."

They are not final, however, and still need to be approved by the so-called "deputies committee" headed by Deputy National Security Adviser Robert M. Gates, where business and Commerce Department opposition is likely to surface, administration officials said. These officials are arguing that export controls work only if they are enforced by a multilateral agreement, such as the Coordinating Committee for Multilateral Export Controls (Cocom) that set Cold War curbs on sales to the Soviet Union and its East Bloc satellites.

A State Department official said the new regulations would contain a list of "bad guys" -- countries that are suspected of having clandestine programs to develop a nuclear capacity, missiles or chemical and biological weapons -- as well as names of special projects, companies, front organizations, industries and government ministries that U.S. exporters should be wary of.

The government also would list a wide variety of products, most with civilian uses, that could be crucial to a weapons project. Among the products likely to be covered, industry sources said, are personal computers, semiconductors, machine tools, software that controls computer-assisted design and manufacturing processes, telecommunications equipment and some basic chemicals.

In presenting the proposals to an aerospace industry meeting last month, the State Department's Clarke was described as being "very emotional" as he spoke of films showing U.S. computers whirring away in an Iraqi missile control center as a reason for quick approval of the export curbs.

During that meeting, Clarke told aerospace executives that they would have "blood on {their} hands" if Iraq launches a poison-gas attack against American troops in Saudi Arabia, said an industry official present at the closed-door briefing.

"We are furious," said one industry source. "There was a tone there that says if we don't favor strong unilateral controls, we are anti-American and blood is on our hands."

The Aerospace Industries Association responded with a letter from its president, former Florida congressman Don Fuqua, to Deputy Secretary of State Lawrence Eagleburger asserting that unilateral controls would hurt America's ability to win broad international support for its nonproliferation measures and would divert business from the United States to countries that don't put the curbs in place.

"It is absolute folly and reflects both arrogance and ignorance to think that the United States can enforce such curbs by itself," said William T. Archey, international vice president of the U.S. Chamber of Commerce, which sent a letter to Secretary of State James A. Baker III opposing the State Department proposals.

Kenneth W. Dam, an IBM vice president who was deputy secretary of state in the Reagan administration, telephoned Eagleburger to object to the sweeping and unilateral nature of the proposals.

A State Department official brushed aside industry objections, saying executives such as Dam overreacted to the proposals because "some people scared them." The official, who spoke on the condition that his name not be used, said the new rules "would have very little effect on U.S. business. But they would plug some holes" in current nonproliferation efforts.

He insisted, furthermore, that the best way to get other nations to adapt similar rules "is to show by example that we are willing to do it ourselves."

President Bush, meanwhile, was urged yesterday by 67 senators not to follow Baker's advice that he veto legislation recently passed by Congress requiring trade sanctions against U.S. and foreign companies that aid the development of chemical and biological weapons in Iraq and other countries. The sanctions are separate from the measures proposed by the State Department. The senators described as "a very abstract judgment" Baker's concern that sanctions would hamper U.S. foreign policy flexibility.