ANNAPOLIS, FEB. 10 -- A few hundred truckers, building contractors and highway safety enthusiasts converged here today for one of the Maryland General Assembly's most enduring traditions: debating whether truckers should be compelled to cover their loads.

This marked the 26th consecutive season of the campaign here to require tarpaulins on trucks in an attempt to cut down on injuries, shattered windshields and roadway debris from gravel and other objects that spill from open truck beds. Each year, the effort has fallen victim to the vehement opposition of the trucking industry.

For this latest round before the House Environmental Matters Committee, the tarpaulin proponents came armed with pathos, petitions, statistics and a "rock of ages" -- a rock that Sen. Howard Denis (R-Montgomery) says fell from a truck years ago and that he keeps atop his desk as a souvenir of his 11-year campaign for covers.

"For years, we've carried this message and it's fallen on deaf years," said Sen. Ida G. Rubin (D-Montgomery), a longtime sponsor. "I have brought out all the guns I can bring out this year."

But judging by the reaction of committee members, the campaign against open trucks may fare no better in 1988 than it has since 1962.

"I've followed many a truck and never had a windshield broken," said Del. Anthony M. DePietro (D-Baltimore), challenging the necessity of the bill.

"We probably have one of the 10 most stringent truck-load laws in the nation now," said Del. Michael H. Weir (D-Baltimore County).

Currently, nine states require trucks to cover their loads. Virginia's General Assembly is considering such a requirement. Maryland is one of 10 states that allow trucks to be uncovered only if their contents do not extend six inches beyond their sides or back.

Last year, a covered-truck bill passed in the state Senate, although it stalled in the House's environmental committee.

Impatient with the legislature, the Montgomery County Council took matters into its own hands last fall, passing an ordinance that requires trucks to be covered while traveling on the county's roads.

Today, Prince George's County Executive Parris Glendening told the legislators he was prepared to ask the County Council to enact a similar ordinance if the bill failed in the General Assembly again this year. But, he said, "a uniform statewide law for Maryland would be much better."

Opponents -- primarily the trucking industry and its supporters -- contended the covers would be expensive and would endanger truckers who would have to climb on their vehicles to fasten them. And they said that trucks weren't a major cause of broken windshields. "We're not the enemy. We're not ogres," said Harvey Epstein, lobbyist for the Maryland Association of Builders and Contractors.

But, according to testimony today by the Washington area chapter of the American Automobile Association, Maryland drivers in 1986 filed 36,000 insurance claims for broken windshields, most caused by debris from uncovered trucks. They cost a total of $6.4 million to repair, according to AAA figures.

Others said the damage is greater. William Varrieur of Gaithersburg said his daughter was killed after a mattress slid off a truck into her car's path. "I hear some of you saying about the cost and all that. But there is no way you can replace an only child who died as the direct result of an uncovered truck."