I takes 28 pulverizers, each crushing 60 tons of coal an hour, to feed the two massive boilers at the General James M. Gavin power plant, a behemoth with stacks twice as high as the Washington Monument rising along the banks of the Ohio River.

Gavin can generate 2,600 megawatts of electrical power every hour--about half the generating capacity of Washington's Pepco system--and in the process it burns 7 1/2 million tons of coal a year. Sixty percent of it is high-sulfur coal mined in Ohio.

The coal rolls in by conveyor belt, an umbilical cord connecting Gavin with the Meigs No. 1 mine 10 miles away. In 1980 more than 375,000 tons of sulfur dioxide, a lethal byproduct from burning that coal, poured from the top of Gavin's lofty stacks. The stacks keep the sulfur dioxide away from the Ohio River, the rich, rolling farmlands of Meigs County, and the 395 residents of Cheshire.

But it doesn't just go away. At its most basic, the problem posed by the phenomenon known as acid rain can be expressed by a simple axiom: What goes up, must come down. The sulfur dioxide undergoes a chemical change in the atmosphere, mixes with moisture and comes down as sulfuric acid in the rain and snow hundreds of miles away, killing vegetation and aquatic life, corroding metal and stone.

When Canadian and American scientists and environmentalists look for the villains in the acid rain problem, their eyes fall on Gavin and dozens of other coal-fired power plants that line the Ohio and other rivers in the coal-rich Ohio Valley.

The people who run Gavin think that's a cheap shot.

"Utilities have historically been an easy target. They're politically vulnerable," says A. Joseph Dowd, an executive with the American Electric Power Co. "It's an administrative convenience to deal with several large sources of pollutants."

That AEP is responsible for several large sources of pollutants is not in question. In 1980, Gavin emitted more sulfur dioxide than any other power plant in the United States. Many of the 18 other coal-fired power plants owned by AEP weren't far behind.

But the utilities point out that acid rain can be caused by more than coal-burning. Automobiles, for example, give off nitrogen oxide, which undergoes the same kind of chemical changes in the atmosphere. Scientists put the acidic composition of acid rain at about two-thirds sulfuric acid and one-third nitric acid, and there is some evidence that the nitrogen oxide in the atmosphere may be of additional importance as a catalyst for the formation of acids.

Dispute continues over which ingredient of acid rain causes how much damage and precisely where. But several things are clear: The problem will cost billions to resolve, coal is a major culprit, and electric utilities are the main users of coal.

AEP burns more than 43 million tons of coal every year, much of it high-sulfur coal from its own mines. As pressure grows here and in Canada to reduce sulfur dioxide emissions as a remedy for acid rain, AEP stands to lose on two counts, both of them costly to AEP and to Ohioans. It could be forced to give up its high-sulfur coal mines and use higher-priced low-sulfur coal, potentially throwing hundreds of Ohio miners out of work. Or it could be compelled to clean up its act with expensive equipment to "scrub" the sulfur dioxide from its emissions. Either action would boost electricity rates charged to AEP's customers.

But AEP doesn't think that will happen. It is counting on political pressures and economic arguments to stay its sentence.

"When you come down to deadlines, when the United Mine Workers are running through the halls of Congress, they'll do what is euphemistically called a midcourse correction," Dowd says.

Behind the bravado of Dowd's words lies a very real concern in the Ohio Valley. Unemployment levels here are hovering around 14 percent. The industrial plants that draw their power from the Gavins of the area are reeling under the effects of a nationwide recession.

If the kind of acid rain remedies proposed by Canada or contemplated by Congress became law, Dowd told the Senate Energy and Natural Resources Committee last month, it would be a "knockout blow to local economies in the Midwest which are already on the ropes."

What most worries AEP and other utility companies is the acid rain provision contained in the Clean Air Act rewrite approved by the Senate Environment and Public Works Committee. That provision would force an 8-million-ton reduction in emissions over 12 years in a 31-state area east of and bordering the Mississippi River.

Utility companies and the coal industry are fighting that legislation with a barrage of figures that even Dowd acknowledges are "so astounding that nobody believes them but us."

AEP says that electricity rates would increase by more than 50 percent for its residential customers, by nearly 80 percent for industrial users. The National Coal Association, quoting figures from the United Mine Workers, says that more than a third of the coal-mining labor force would be affected, and $6.6 billion in income would be lost every year.

"It's very difficult for a congressman to be courageous when he's confronted with this kind of cost data," says one Capitol Hill aide.

Environmental groups say the industry figures are a lot of hooey, and they back up their assertions with cost studies of their own.

A recent congressional comparison of two of the cost analyses--one done for the Edison Electric Institute, an industry group, and the other for the National Wildlife Federation and the National Clean Air Coalition--found that the annual costs would range between $2.4 billion to $4.6 billion in 1990. That translates into a 2.4 to 4.6 percent increase in electricity rates, the study said, and it added that the 10 states most heavily affected by the Senate provision "would still enjoy a significant advantage in lower electricity rates than the other states in the reduction program."

But the congressional study also included a caveat, one of particular importance to AEP and other users of local high-sulfur coal: One of the least expensive methods of reducing sulfur emissions is simply to switch to lower-sulfur coal. Neither study explored the impact of high-sulfur coal states taking action to protect that critical industry by forbidding such switching.

"The practical political reality is that in those states we would never be permitted to switch," says Dowd.

There are a lot of practical political realities at work in this debate, and one of them involves an administration that came into office promising to cut back on expensive regulation and put a foundering economy back on its feet.

With that goal clearly in mind, virtually every agency of the Reagan administration, from the White House and State Department to the Energy Department and the Environmental Protection Agency, has come out solidly against enactment of the Senate acid rain provision or anything like it.

Their key argument is that the scientific evidence does not support costly new regulations. But in her 9th floor office at EPA headquarters in Washington, Kathleen Bennett, associate administrator for air pollution programs, is quick to acknowledge that she is not a scientist. She is a regulator, operating under the purview of cost versus benefit. What she wants, in effect, is some solid evidence that a cutback in emissions at point A will ease acid rain damage at point B.

"There is no nation on earth more willing to control air pollution than the United States," she says. "But you cannot explain to the people that it will save a single lake."

Bennett contends that an effective, though less immediate, mechanism for curbing acid rain is already in place -- the Clean Air Act, the rewrite of which is stalled in the House and unlikely to come up for action soon in the Senate.

EPA notes that emissions have already dropped by 5 million tons under the provisions of the 12-year-old Clean Air Act, and under its provisions, new sources of pollution are required to meet stringent "new source" emission levels. EPA says the result, as older and less efficient power plants go out of service over the next couple of decades, will be a gradual lowering of emissions.

"In 1995, we'll be at exactly the same place as called for in the Senate acid rain provision , without spending a minimum of $30 billion," Bennett says.

Environmentalists dispute that prediction. In the first place, they say, the acid damage problem is cumulative and its solution cannot wait until 1995. In the second place, they contend that the history of enforcement under the Clean Air Act has not been exemplary. "States have until 1985 to meet 1980 reductions," says Liz Barrett-Brown of the Natural Resources Defense Council. "We're 1.5 million tons away from achieving that."

Meanwhile, utility officials and environmental protectionists in Ohio aren't above doing a little finger-pointing of their own on this subject, suggesting that Canada and the northeast states are the cause of their own distress.

"Those guys have about the worst record in the world," Wayne Nichols, director of Ohio EPA, says of Canada. Dowd is fond of displaying a chart that shows the pollution densities in New Jersey and Massachusetts are nearly as high as that of Ohio, when nitrogen oxide is added in.

Canada is acutely aware that Canadian auto emissions standards are significantly looser than those in the United States, and that the massive INCO nickel and copper smelter, whose 1,250-foot-high "superstack" is the biggest single emitter of sulfur dioxide in North America, sits on the edge of the Georgian Bay just 150 miles north of Ontario's sensitive Muskoka-Haliburton lake country.

But Canada says it is taking steps to bring its polluters into line. In the mid-1960s, INCO was putting 7,000 tons of sulfur dioxide into the air each day. It isn't putting any in the air now -- it is closed down as a result of soft world markets -- but when it reopens, it will be under government orders to keep its emissions below 2,500 tons a day and then cut them even further, to 1,950 tons a day.

Ontario Hydro, Ontario's major utility company and the second largest contributor of airborne pollutants in the province, is under similar orders to cut its emissions.

Their actions have so far been met with skepticism in Washington. "They're saying we'll control 50 percent if you will, and we'll start when you start," says Bennett. "Start? We've been at it for 12 years."

Utility officials, and their supporters in the Reagan administration, suspect that there is a dark ulterior motive to Canada's concern over acid rain. Forcing U.S. utilities to jack up their rates to pay for expensive emission control programs, they say, will leave an open door for the export of power from Canada's nuclear and hydroelectric generating plants.

"They are using it to advance the sale of power," said Dowd. "There is an enormous amount of generating capacity in that country. They have no market for it in Canada. It's pretty easy to see what will happen."

The theory gained prominence recently when Ontario Hydro and General Public Utilities announced a joint project to bring Canadian electricity into Pennsylvania and New Jersey through a cable under Lake Erie. That project eventually fell through -- for economic rather than diplomatic reasons, Canada insists -- but it added considerable fuel to the controversy.

The Canadians deny that they have any aspirations to set themselves up as massive exporter of electric power to the United States, and a recent congressional report found that "Canadian electricity probably cannot be substituted on a significant scale for U.S. coal-fired capacity because of technical, regulatory and political contraints."

But the utilities are skeptical, and they have added the electricity conspiracy theory to an arsenal of other arguments against acid rain legislation.

"The industry campaign is highly organized and financed," says NRDC's Barrett-Brown. "All they have to do is cloud the issue."

In a circular included recently in electricity bills, AEP urged its customers to write to their congressmen in opposition to the Senate bill. It was headlined: "Spend 20 cents to save yourself thousands of dollars."