At least two agricultural workers on the east coast of the U.S., and several on the west coast, have died this summer after accidentally swallowing paraquat, the weed killer sprayed on Mexican marijuana crops.

While there is much debate about the effect the herbicide may have on American marijuana smokers, there is no doubt the chemical can kill if even small amounts of it are swallowed, said Dr. James F. Winchester, assistant professor of medicine at Georgetown University Medical Center.

There were 230 cases of fatal paraquat poisoning reported in the world medical literature up to 1973, said Winchester, and at least one murder has been committed with the tasteless, ordorless weed killer.

According to Winchester, as little as single mouthful of a 20 percent solution

A general herbicide manufactured in several forms by Chevron Chemical Co., paraquat has been marketed for more than a decade under such names a Ortho-Paraquat CL and Ortho Spot Weed and Grass killer.

According to Winchester, as little as a single mouthful of a 20 percent solution of paraquat can kill an adult in about four days. Just tasting the substance can kill a child, he said.

"It is a horrible death," said Winchester, "because they all die wide awake." The chemical destroys the ability of the lungs to pick up oxygen, he said, and the paraquet victim dies of slow suffocation.

Gregory Shiflett, an extremely lucky Winchester, Va., 15-year-old, knows what Winchester means.

Shortly after midnight July 18 Shifflett awoke in his bed suffering from shortness of breath. "I couldn't breathe," he said yesterday, "and my muscles started shaking."

Shiflett's parents took the youngster to a local hospital, where he told the emergency room crew that nine hours earlier he had drunk from a hose being used to fill an orchard spray tank containing paraquat.

But "they said there was nothing wrong with me" said Shiflett, who was then taken home. The next day the hospital called, he said, to say blood tests had turned up nothing. By then Shiflett was feeling all right and was not even concerned when a second call from the hospital reported another test had turned up paraquat traces.

The third night, however, Shiflett again awoke with tremnling muscles, difficulty in breathing, and this time, he had open sores in his mouth and throat. The sores, said Winchester, were not caused by the paraquat, but rather, were caused by a chemical mixed with the weed killer in the tank.

Shiflett was again taken to the local hospital where he was admitted, and the next day he was transfererd to Georgetown.

Physicians at Georgetown had Shiflett drink a form of natural clay and then gave him a drug to move the clay through his system. The clay, said Winchester, removes the paraquat from the gastrointestinal system.

In addition, Shiflett underwent charcoal hemoperfussion, a treatment in which the patient's blood is removed from his body through an artery in his arm, passed through a charcoal filter, and returns to a vein in the arm. Shiflett's blood was cleansed in this manner for about eight hours.

Shiflett suffered mild mamage to the lungs, said Winchester, up to 60 paraquat deaths a year have been reported in Great Britain, including a case in which a woman in Scotland killed her husband by cooking up a paraquat-seasoned stew.

"In the old days, it seemed, it used to [cause] accidental poisoning," said Winchester. "But it's been the impression of more and more people that there've been more suicides with it, which is very curious" because the poison causes such a horrible death.

One of the major dangers of paraquat, said Winchester, is the fact that it looks "exactly like cola, which is why people drink it [accidentally]."