If politics makes strange bedfellows, it might be said that the law makes stranger ones.

And now the Chemical Manufacturers Association and the Environmental Defense Fund, which often find themselves on opposite sides of environmental issues, have joined forces in a lawsuit against common foes: the Environmental Protection Agency and the Health and Human Services Department.

Both want to force the government to collect more data on the relationship between toxic chemical waste and human health, as the 1980 Superfund Act on hazardous waste dump cleanups directed the government to do.

This is not to say that the chemical firms and the environmentalists see entirely eye to eye on the issue. The chemical companies say they believe there is no established connection between toxic chemicals and human illness. The environmental group says it thinks the link is well established. Both expect the new studies to confirm their opinion.

The Superfund law tells HHS to establish, with Superfund money, a special Agency for Toxic Substances and Disease Registry, which would be responsible for providing emergency care to persons exposed to toxic chemicals and would conduct a variety of tests to see what effect the exposure had.

Mindful that many of the ailments believed to be linked to toxic chemical exposure--including cancer, infertility and genetic damage--take years to show up, Congress envisioned the new agency as a way of monitoring victims over a long period.

But more than two years after the Superfund law was signed, HHS has not set up the new agency. When Rep. James J. Florio (D-N.J.), one of the architects of the Superfund Act, questioned then-HHS Secretary Richard S. Schweiker on the subject last summer, Schweiker replied that the administration had introduced legislation to rescind the requirement. And anyway, Schweiker added, the Centers for Disease Control in Atlanta already handles that kind of work.

The EPA, meanwhile, has been reluctant to part with the $5 million or so of Superfund money that would be needed to get the new agency under way.

The administration's Superfund amendment didn't get anywhere, however, and there was some question about whether the CDC was doing the same work that Congress wanted done under the Superfund law.

So in December, the environmentalists filed suit in the U.S. District Court here, complaining that while the agencies were dragging their feet "the opportunity to conduct studies on those exposed to toxic substances is being lost."

Earlier this month, the Chemical Manufacturers Association said "amen," pointing out in its petition that the bulk of Superfund money comes from its members' pockets, and the way it is spent is of considerable concern to them.

The question of links between toxic substances and health is being given even more impetus these days because of moves afoot on Capitol Hill to expand the Superfund concept to compensate the victims of toxic waste dumps, not just to clean up the dumps.

Bills introduced last year, expected to resurface this year, would set up an additional multibillion-dollar pot of money for that purpose, most likely from another tax on chemical and oil sales.