After six years of political skirmishes and legal battles, the Environmental Protection Agency yesterday issued its final standards for disposing hazardous waste on land.

Completion of the standards, which were rewritten dozens of times over the years, essentially completes the cradle-to-grave hazardous waste disposal program that Congress directed EPA to establish in the Resource Conservation and Recovery Act of 1976.

The standards, which will take effect in six months, are designed chiefly to prevent hazardous chemicals from contaminating underground drinking water. EPA estimates it will cost industry $150 million to $460 million to meet the standards.

For years, land disposal was considered the easiest and cheapest method of disposing hazardous wastes. But the Love Canal and other incidents alerted the public to possible health dangers and created a clamor for federal regulation.

In February, EPA's decision to temporarily lift a ban on disposing liquids in landfills resulted in protests from environmentalists, state officials and community groups. A month later, EPA imposed a revised ban, allowing small amounts of liquids to be disposed in containers. The final regulations retained those standards.

Despite strong public support for regulation of hazardous waste, the land disposal rules have been a long time coming, in part, because EPA has had trouble balancing the arguments of those who say there is no way to build a safe landfill and landfill operators who say that strict standards would put them out of business.

EPA took a compromise position by requiring new facilities to install a synthetic liner to keep liquids from seeping into the ground or water table and a system to collect and remove liquid within the landfill, while exempting existing facilities from those standards.

EPA estimates that new small facilties, which will have to bear the largest expenses, will pay an additional $15 per ton of hazardous waste handled, doubling their current costs for environmental controls. Existing facilities will have to pay an additional $7 per ton, EPA estimates. These facilities charge from $55 to $240 per ton for disposing waste, according to EPA.

While praising the standards for new facilities, the Environmental Defense Fund criticized those for existing ones. "The agency's own data indicates a significant number of existing facilities are unlined and are located directly over a groundwater source," said EDF attorney David Lennett. There are approximately 2,000 existing land diposal facilities.

But EPA Assistant Administrator Rita Lavelle said, "It's a realistic approach. You just cannot ban an existing technology overnight unless you have an alternative."

Michael Cook, acting director of the Office of Solid Waste, added that requiring landfill operators to install or replace old liners "could be dangerous because you would have to dig up the hazardous waste."

But Cook said that operators of existing facilities will have to monitor groundwater in the area, and if contaminants are spotted, they will have to take "corrective action." Firms that do not clean up the water quickly and stop the leak will be fined.

Hugh Kaufman, an EPA staffer and outspoken critic of the agency's policies, said the problem with that approach is that once a water supply is contaminated, there is no way to completely recover it.

Kaufman also said that even synthetic liners leak, and industry and agency experts agreed that the liners are far from fool-proof. The seams of synthetic liners can break, the liner can be punctured, laid out incorrectly, corrode or react with the hazardous waste and decompose. But EPA believes they are superior to clay liners.

Kaufman also contended the program will require a large pool of EPA professional staff, "and this administration is cutting those resources."

Richard L. Hanneman, director of government affairs for the National Solid Wastes Management Association, which basically supports the new standards, questioned the agency's insistence on synthetic liners, given the problems.