The State Department is testing ways to make marijuana stink. Literally.

The department, caught between irate pot smokers and a huffy Mexican government, wants to keep spraying paraquat, a herbicide, on Mexican marijuana, but it would add a foul-smelling chemical to warn users.

The chemical, known as d-Limonene Dimercaptan (dLDM). is made from orange peels, but is variously described by government officials as smelling like "essence of skunk," "burning tar" and "poo-poo."

Leslie Alexander, a State Department narcotics official, said yesterday that a team of scientists from the departments of Agriculture, and Health, Education and Welfare and from the Environmental Protection Agency and the University of Mississippi sprayed small Mexican marijuana fields with the stinky substance two weeks ago and in April.

"It looks promising," he said. "It seems to be the best thing going."

The State Department is desperately trying to develop a marker to identify paraquat, to avoid canceling the spraying program that has caused a raging controversy among the nation's estimated 16 million marijuana smokers.

The department gives Mexico $9.5 million a year to spray marijuana and poppy fields. If funding is cut off, Mexico has announced that it will continue spraying anyway. State Department officials are worried that Mexico will cut back on poppy spraying, however, thus increasing the flow of heroin to the United States.

Paraquat kills marijuana plants within 48 hours, but within that time it can still be harvested and shipped to smokers, who now have no way of knowing that it is contaminated.

Meanwhile, government officials can't agree on whether paraquat is really harmful.

Congress last year told HEW to decide if it is hazardous and inform the State Department accordingly. If HEW Secretary Joseph A. Califano Jr. decides it is, and he is heading in that direction, then the State Department must either cut off funding for marijuana spraying or devise a warning marker.

Two weeks ago Califano wrote EPA and the Agriculture Department that, "based on computer simulation studies, we estimate that 50 to 100 marijuana smokers in the southwest are exposed each year to 500 micrograms or more of unaltered paraquat in marijuana smoke. This dosage is potentially capable of producing a toxic effect in the lungs of these smokers."

Califano also estimated that 2,000 south-western smokers are exposed to between 100 and 500 micrograms of paraquat, producing "less severe lung damage." Fewer than 1 percent of marijuana samples collected by HEW on the East Coast contained paraquat, compared with over 12 percent in the southwest.

Rep. Lester L. Wolff (N.Y.) said the people who oppose paraquat "are trying to make a tempest out of a pot." Wolff, chairman of the House Select Committee on Narcotics Abuse and Control, said most regular users have switched to Colombian Marijuana because it is stronger.

"I seriously question any of the effects of paraquat except on someone so heavily abusing marijuana that he would probably die from an overdose of smoke before the paraquat could kill him," Wolff said.

Toxicologists from the federal Center for Disease Control, which conducted studies for Califano, and from the Mitre Corp., which compiled the State Department's environmental impact statement, conflicted sharply at a committee hearing yesterday.

"I think paraquat, even if inhaled in very small amounts, can damage the lungs," said Dr. Rinate Kimbrough of the CDC.

Mitre's Richard Thomas testified, "At very low concentrations, no effects would be expected."

Thomas added that "heavy use, such as 10 cigarettes over a few hours, could lead to more substantial [pulmonary] effects."

Although Kimbrough testified that paraquat accumulates in the lungs for an extended period of time, Thomas said, "Paraquat is not a long-term cumulative toxin. Therefore, the expected contamination levels should be too low to cause irreversible lung damage except when the use rate is extra-ordinarily high."