When the tanker Argo Merchant grounded off Massachusetts in December with its cargo of 7.6 million gallons of oil, the U.S. Coast Guard mobilized hundreds of men and millions of dollars worth of sophisticated equipment to cope with the spill.

They tried to pump the oil from the sinking vessel. They tried to ignite it. They considered using chemical dispersants. But 50-knot winds and 15-foot waves left them helpless as the viscous black jelly drifted out to sea.

The technology to cope with oil spills is in its infancy, but it is growing fast - and it must to deal with some 10,000 incidents a year in the United States alone.

At an oil spill conference here this week, companies from coast to coast set up 90 exhibits, attesting to the boom in the cleanup and prevention business. Technical papers presented by government and industry researchers documented a bewildering profusion of new equipment from simple rubber containment barriers to satelite trackling systems.

Until the late 1960s, no one bothered much about oil spills. Scores of attacked tankers had spilled oil off U.S. coasts during World War II, and Mother Nature was left to gradually absorb the mess.

But in 1967, the Torrey Canyon tanker spilled 30 million gallons of oil off the English coast, killing thousands of birds and fouling several hundreds miles of shore. The incident sparked worldwide concern, prompting President Johnson to recommend legislation to help prevent spills here.

After a 1969 blow-out at an offshore rig near Santa Barbara, Calif., Congress passed the Water Quality Control Act of 1970, forbidding discharges and providing for cleanup.

The first national oil spill conference was held in 1969 and, says Kenneth Biglane, the Environmental Protection Agency's oil spill expert, "I liken the equipment in those days to baling wire and kite string."

Now, he said, "industry is in its second and third generation" of technology.

On the Gulf and West coasts, oil companies have organized 100 cooperatives, stockpiling $14 million woth of cleanup equipment. More than 50 contractors have gone into the oil spill cleanup business. Large companies like Lockheed and General Electric are designing and manufacturing new devices.

Technology is still lacking to clean up spills in heavy seas such as those off New England and Alaska, and in the Arctic, where offshore oil exploration has recently begun. However, great progress has been made in equipment for calm waters and slower-moving rivers.

A Coast Guard research program has developed high capacity pumping systems which can be delivered by helicopter to stranded tankers, and boats with skimmers that slurp oil off the ocean surface.

The Navy's latest experiments, described in a paper here, use a machine to distribute polyurethane absorbent chips which soak up oil, then gather them and remove the oil.

The object is to catch the oil before it hits shore. Once it has settled onto beaches, not much can be done other than to haul the sand away, often manually, since beaches generally have poor access and can be ruined by heavy equipment.

Although elaborate volunteer efforts are mounted to rescue oil-coated birds after a spill, studies have found that the birds often die from mishandling and from cleansing agents that eliminate natural insulating oils. Some wildlife experts contend it would be more humane to kill the birds quickly and replace them through a hatchery program.

About 30 per cent of all spills are "mystery spills" where the polluter - often a tanker cleaning out oily ballast water - escapes without notifying the government. To find the culprits, the Coast Guard developed an "oil fingerprinting" system.

Sophisticated techniques are used, including infrared spectroscopy, which measures an oil compound's absorption of infra-red radiation. Since each oil cargo varies, the Coast Guard can match oil from a spill with oil delivered by an individual tanker.

This technique was used to track down the tanker Garvis, which fouled Key West beaches in July, 1975. The Coast Guard checked 247 ships from Maine to Texas, comparing oil samples from 50 cargoes, before discovering the guilty tanker.

To clean up the Torrey Canyon spill, the British used thousands of pounds of detergent and chemical dispersants, which caused more damage marine lift than the oil did, biologists later found. Ever since, use of chemicals on oil spills has been a continuing controversy. Rarely used in the United States, they are a preferred method in Europe.

However, modern biodegradable dispersants, a vast improvement over the primitive compounds of 1967, have been developed and should be used more here, according to a paper presented by an Atlantic Richfield Co. scientist. Dispersants break up the oil so that it can be more rapidly absorbed by water and marine organisms.

Whatever the method, a willing band of businessmen is on hand to service what has become a multimillion-dollar industry. One company that exhibited here, Marine Pollution Control of Detroit, advertises its work force as "Minute Men of the Environmental Age."

"Everyone here has to have a sense of imagination as each spill occurs," says company President David Usher, who also heads the industry's trade group, the National Oil Spill Control Association of America. "Each time is different. It's like fighting a war . . . we're fighting a war with pollution."