THE ENVIRONMENTAL movement has merged with the civil rights movement in a poor, rural county in North Carolina. The people of Warren County, black and white, seem united in opposing the new toxic waste dump opened by the state, with the Environmental Protection Agency's approval, in their back yard. Old-time civil rights organizers have converged on the area, using old- time protest tactics to make their point.

Why did the state choose Warren County as the site for its first toxic waste dump? The state says it's a matter of science and economics; the protesters say it's politics--the county is poor and largely black. After years of haggling, a court case and innumerable meetings, the dump is operating. Peaceful protests have resulted in nearly 500 arrests, including that of D.C.'s own delegate to Congress, Walter E. Fauntroy.

It is naive to believe that major decisions about where to put noxious or otherwise controversial facilities can be made totally independent of political calculations. These factors will weigh on the minds of decision-makers, whether the subject is a dump for lethal chemicals, a nuclear power plant, a prison or a highway. Science can inform the choices, but it can't resolve the toughest, most uncertain tradeoffs between risks and costs, or ensure fairness.

So blacks and whites in depressed Warren County are right not to let the bureaucrats and technicians invoke studies as some kind of cloak of immunity. It does not strike us as entirely implausible that the residents' political vulnerability had something to do with the decision. Indeed, soil scientists advising the protesters argue that other sites would better meet EPA standards. Disposal of toxic wastes inevitably involves some risks, if only because the experts are unsure about long-term health risks and the safety of various storage techniques. Since the wastes have to go somewhere, some community will end up dissatisfied. Thankfully, the PCB-contaminated soil at issue here is less of a storage risk than liquid or radioactive wastes.

Whatever the merits of the Warren County controversy, we can celebrate the marriage of civil rights activism with environmental concerns. Environmental choices, like economic ones, have profound consequences for all races and classes. Accounting for all of those diverse interests takes both science and politics. It is good to see a broadening of the traditionally white, upper-middle-class environmental movement.