HERE'S A SITUATION in which three combatants -- business on one side, environmentalists on the other and a regulatory agency in the middle --managed to escape the familiar regulate-and-litigate syndrome. How did they do it?

Controversial regulations to control the pollution of water by the steel industry were proposed in "final" form by the EPA last May, after nearly a decade of efforts through four administrations and numerous court suits. The law sets a July 1984 deadline for companies to limit their effluents (water pollution, that is) to levels at or below those attainable with the "best available technology economically achievable." The task is enormously complex for both industry and government.

This regulation, affecting only steel, identifies various categories of pollutants produced in each of many manufacturing subprocesses and defines pollution limits for each. Of roughly 700 such specifications in EPA's May regulation, the industry challenged about 30 as being based on faulty information. On the other side, the Natural Resources Defense Council challenged EPA's use of a "bubble" concept, whereby a plant would be able to make cost-saving tradeoffs among effluent sources, so long as aggregate pollution results were no worse. So everyone went to court.

In October, however, the parties began an arduous negotiation process in the hope of avoiding the vicissitudes and delay of the federal courts. The industry's interest lay in ending the uncertainty--the sooner the regulations are completed, the more likely it is to be able to meet the statutory compliance deadline. And the Natural Resources Defense Council has a general concern to speed things up since the steel regulations were only the first of many industry-wide regulations to be published as final, and more regulatory delays would invite Congress to extend statutory compliance schedules. Both parties also knew that even a victory in court would simply send the issue back to the agency for another round, the outcome and timing of which were impossible to know. In the settlement announced last week, the industry won concessions on the technical numbers, and its antagonists won a modification in the bubble provisions.

This settlement is one of those occasional signs that there are alternatives to protracted, unproductive interest-group warfare. Unfortunately, it took many years plus the pressure of pending litigation even to bring the parties to the bargaining table. Meanwhile, the environment has suffered and the industry has labored under uncertainty. Participants in the steel effluent negotiations praise the unusual combination of circumstances, personalities and good faith that permitted a happy settlement. It's commendable. Why must it also be so unusual?