The Environmental Protection Agency has failed to supervise or enforce effectively settlements with corporate polluters to clean up their toxic wastes under the Superfund program, the General Accounting Office reported yesterday.

The GAO said bureaucratic red tape, lax enforcement and corporate misrepresentation have delayed cleanup of some of the nation's worst hazardous-waste sites for as long as two years.

"EPA does not have a coordinated, systematic structure for overseeing [corporate] compliance with settlement terms," the GAO said. "Settlement oversight and enforcement decisions are left to to each project manager's judgment, without the benefit of formal guidance, procedures and documentation standards."

The report was designed to evaluate the EPA's efforts under Superfund to have industrial polluters perform cleanups.

The agency negotiates settlements with individual polluters, known as "responsible parties," and requires specific schedules and standards for each cleanup. If negotiations break down, EPA can clean up the site and sue the polluter for the cost.

Rep. James J. Florio (D-N.J.), who released the report, said it indicates that the program originally designed for emergency cleanups has turned into "delay after delay, with no effective enforcement."

Jack Stanton, the Superfund's chief enforcer, said cleaning up such problems as contaminated water supplies is time-consuming. But the EPA, he said, accelerates cleanups of toxic dump sites whenever they threaten public health or safety.

The GAO limited its analysis to 39 of the 131 settlements in which polluters had agreed to cleanups valued at $370 million. Of the cases sampled, the GAO found problems with 25.

The largest problem stemmed from companies' "inadequate" analyses of the extent of pollution to be cleaned up, according to the GAO. In some cases, EPA officials told the GAO that polluters "intentionally biased reports by misrepresenting the extent of site contamination in an effort to obtain less extensive and probably cheaper remedies."

The EPA's rejections of those analyses resulted in cleanup delays ranging from one month to two years, the report said, with postponements often lengthened by EPA tardiness.

Meanwhile, toxic wastes such as arsenic moved further into several communities' water supply, said the report, which did not name the communities.

The report also faulted the EPA for inconsistent and lax enforcement of its agreements with polluters. Only two of the 25 problematic cases cited by the GAO resulted in penalties.

In one, the polluter was fined $9,000 for a late presentation of an engineering study. But no fines were levied in another case where cleanup was delayed for two years because of poor company presentations.