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Emissions Test Anxiety

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Does the Northwest Incinerator really put 17 pounds of lead into the air every hour? That would be 150,000 pounds a year, and it would make the incinerator the largest lead polluter in Cook County by a factor of about 100. (The next largest--a recycler of nonferrous metals--gives out about 1,500 pounds a year.) Members of the anti-incinerator coalition WASTE say it does; William Abolt and Henry Henderson of the city's Department of Environment say the claim is no longer true and WASTE knows it.

There's no question that it was true in the spring of 1993. That's when a city-employed, EPA-supervised testing company measured lead emissions from one boiler at 5.7 pounds per hour, roughly 7 percent of the total 80 pounds of particulates being emitted from that boiler in the same time.

After a little more than a year and a little less than a million dollars, in July 1994 another city-employed, EPA-supervised testing company found that the city had cut the 80 pounds per hour of particulate emissions down to just 7.3 pounds. How much of that is lead? It couldn't still be 5.7 pounds, as WASTE claims, unless most of the trash on the northwest side was made of lead.

But the city, which seemed to have done a good cleanup job, made it hard to say what the true lead figure was, because it changed testing methods. The 1993 testing company measured lead coming out the top of the smokestack. The 1994 testing company, at the city's request, did not measure that number. Instead it measured for lead in two other places: just before the smoke passes through the electrostatic precipitators and out the stack, and in the incinerator ash left over after burning. Lead made up about eight-tenths of one percent of the particulates in both places. And since incinerators don't create lead, Abolt says that means lead had to make up 0.8 percent of the particulates coming out of the smokestack too. "You know the amount in the ash. The ash has the same concentration as what was in the boiler. You couldn't maintain that ratio if more lead escaped [out the stack], because then you'd have less in the ash." That comes out to less than an ounce an hour.

This is not one reduction, but two. The incinerator is giving off fewer particulates and therefore less lead in the 1994 test. And its particulates this time contain a ten times smaller proportion of lead than they did in 1993. Abolt takes credit for the first drop, but not the second. If lead dropped from 7 percent of emissions in 1993 to 0.8 percent in 1994, he thinks that must just reflect a change in the makeup of the garbage burned on that particular day. So, according to the city, on a "good garbage" day, each boiler is supposedly giving off less than one ounce an hour; on a "bad garbage" day, it might be half a pound.

Either way it's a lot less than the 5.7-pound figure WASTE clings to. "The critics of incineration have gotten copies of these [1994] tests from Illinois EPA, pages of them," says a frustrated Abolt. "We've said we'd be happy to go through their concerns, meet with them and IEPA and go through the lead numbers, show where we looked in the furnace and why."

WASTE doesn't trust the city tests anyway (and in its advertisement finesses the issue by describing "150,000 pounds" as "the EPA's most recent emissions test that scanned for lead"). But one of its main experts suggests that the Department of Environment should test more. With readings from a grand total of two days, we have no way to know whether either one is typical.

"It sounds to me like they're just sort of making something up after the fact. Why not test it the same way as before?" grumbles engineer Bill Eyring of the Center for Neighborhood Technology. "One logical conclusion is that they should test a lot more. If they were really trying to learn something, they'd have more than this data which is at best skimpy and at most confusing."

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