Hills are rare in the flat Midwest. But the one standing tall by Mallard Lake in the DuPage County Forest Preserve is especially unique. It is a hill of garbage -- the result of nearly 10 years' worth of throwaways that have been dumped, bulldozed, compacted, and covered with earth daily.
County officials have ruled that the hill shall go no higher. And that decision symbolizes the problem the nation now faces in disposing of its growing piles of solid waste.
Most of America's major cities are rapidly running out of landfill space. About half of them are expected to use up their existing sites within five years. Even in cities where space is not yet in short supply, citizen opposition is discouraging local officials from building new landfills.
In desperation, many communities are turning to incineration, which has been tried with varying degrees of success. By most estimates it can reduce garbage volume by 40 to 60 percent.
Sixty communities are now burning at least some of their garbage, and another 100 are seriously considering it, according to Ron Musselwhite of the United States Conference of Mayors. Many are opting for the older, simpler burners into which almost everything is thrown -- combustible or not. Most of the newer community ventures also produce saleable steam or electricity as a byproduct.
But environmentalists are concerned that cities rushing to use incineration may be trading one set of pollution problems for another. Most are not opposed to incineration per se. But they would like to see a more cautious approach that resulted in smaller and fewer incinerators.
``We're talking about infant technology,'' says Eric A. Goldstein, a New York lawyer for the Natural Resources Defense Council (NRDC). ``Every effort should be made to do it right from the outset and to protect public health, so we don't make the same mistakes we did with the nuclear industry.''
Some garbage burners -- often the newer and more complex variety that call for sorting materials and shredding them before burning -- have had operational problems.
Ohio's refuse-derived fuel facility in Akron, for instance, has had more than a dozen explosions since it opened in 1979. One explosion last December, caused by the mistaken burning of a prohibited oil and chemical substance, resulted in three fatalities and is still under investigation by a grand jury. But the chief concern of environmentalists is air pollution from burning.
Although solid waste landfills technically bar hazardous waste, most landfill operators admit that cans of pesticide, paint thinner, radioactive smoke detectors and other potentially toxic substances often work their way into household and industrial garbage.
And just as ground-water contamination from such solid waste landfills has been a growing problem, so environmentalists are concerned that federal clean-air standards may not be strict enough or comprehensive enough to deal with the range of pollutants produced in burning.
New York City recently decided to install scrubbers in its five planned incinerators to catch acid gases and so-called fabric filters to catch fine particles often mixed with heavy metals. This is considered a partial victory by environment groups.
But NRDC lawyer Goldstein says there is no ready technological control available for the area of greatest concern: the emission of organic compounds such as dioxin.
Municipal sanitation officials and burner manufacturers say European cities have relied on solid-waste incineration for years and suggest that concerns about dioxin are exaggerated. Preliminary studies done for the US Environmental Protection Agency (EPA) indicate that dioxin emissions in solid-waste incineration tend to be very low.
Still, the EPA has recently undertaken a new national dioxin study to determine just how pervasive and dangerous the chemical compound is. ``We need to know more about the health effects before we start regulating it,'' says EPA spokeswoman Vanessa Musgrave.
Many now believe that burning dioxin at a high-enough temperature can effectively destroy its toxic properties. One of the strongest sets of criteria incorporating that theory has recently been imposed by the San Diego Air Pollution Control District in granting the first garbage-burner construction permit in the county. In addition to requiring scrubbers and fabric filters like the New York incinerators, the board requires that solid waste be burned at an average of 2,000 degrees fahrenheit and dioxin emissions be periodically tested and held to a specified level.
``We've tried to deal with the issue through risk assessment, and we're convinced that there won't be any public health danger from dioxin emissions,'' says Paul Smith, the district's deputy director.
Some who closely monitor progress on this issue say those who believe the dioxin problem has been overblown tend to rely on testimony from one set of scientists, while those who believe it to be more serious rely on statistics from other scientists. ``It's not a firm science,'' says Mr. Smith.
``We'd just feel more comfortable if existing facilities were subjected to rigorous testing and analysis to determine exactly what toxic pollutants and how much are being emitted,'' says Goldstein.