Washington — The Environmental Protection Agency is having a hard time getting some of its work done. Tough tasks dealing with toxic pollutants - hazardous substances such as benzene - are piled high in EPA's ''IN'' box. Some examples:
* In three years, the agency has written final permits for 115 hazardous waste dumps. That leaves approximately 7,895 to go. ''The job will take 100 years at this rate,'' one environmentalist grumbles.
* EPA has yet to decide what levels of organic chemicals it will allow in drinking water. The Safe Drinking Water Act, which charges the agency with making this decision, became law in 1974.
* EPA has tested for safety fewer than one-sixth of the active pesticide ingredients produced in the United States. It has taken six years to get that far.
''We are way behind on (regulating) toxics,'' EPA administrator William Ruckelshaus ruefully admits.
The problem here is not lazy bureaucrats who take long lunches and play wastebasketball all afternoon.
Even EPA's critics admit that regulating toxics is a daunting task. For one thing, the book of scientific knowledge on toxic pollutants is very thin. Few specific facts are known about how hazardous pollutants affect human health. And there are so many of them: More than 55,000 chemicals are currently being produced in the US, with hundreds more being added every year.
''I'm not saying this is an easy job,'' says William Drayton, a Carter-era EPA official and author of a book on compliance with environmental laws.
But critics complain that EPA has had to shoulder this tough job while beset by budget cuts and political controversy.
EPA's budget today commands about the same purchasing power as it did in 1973 , Mr. Drayton estimates. Yet since then Congress has passed seven laws charging EPA with regulating toxic pollutants, effectively doubling the agency's workload.
The result of this squeeze, say Drayton and other critics, is that large sections of the new toxic laws - the Resource Conservation and Recovery Act (RCRA), Toxic Substances Control Act, and others - haven't been implemented.
''It's an astonishing pattern,'' he says. ''You go through each area and find that 1 percent, 2 percent of the core tasks have been done.''
Many of the uncompleted tasks involve deciding what substances to classify as ''toxic'' and how closely to regulate them. EPA has been slow to set standards for toxics in drinking water, for instance. RCRA, the law which governs handling of hazardous wastes, has had no new substances added to its ''toxic'' list since 1980.
EPA has finally taken action against three hazardous air pollutants, including benzene, while preparing to regulate four more. Dozens of suspected toxic air pollutants remain ''under assessment.'' Other EPA jobs behind schedule involve permits for pollution-handling facilities. The agency has a thick backlog of applications for license renewals from sewage dischargers, for instance. With only 115 permits written, the licensing process for waste dumps is far off track.
Dump permitting ''clearly has to be increased,'' says J. Clarence Davies, vice-president of the Conservation Foundation.
EPA chief Ruckelshaus, speaking recently with reporters, admitted that his agency is struggling to implement toxic waste laws. But he stressed that the problem is not one caused simply by Reagan officials, but by ''the fits and starts'' of a number of administrations.
And the toxic tasks facing EPA, Ruckelshaus says, are huge.
''The dumps,'' he says, ''are the products of decades of neglect.''
Other administration sources say there has been progress in the last year. EPA has now called in for final study the permit applications of some 2,000 dump sites, according to a report by the Council on Environmental Quality. Standards detailing the levels of volatile organic chemicals that will be allowed in drinking water, the CEQ says, are nearing completion.