NAPERVILLE, ILL. A gas company announced Wednesday that it will test 200,000 homes across Chicago's far northern and western suburbs for possible contamination by mercury, a toxic metal that can damage the kidneys and brain.
The first homes inspected will be those where old-fashioned gas regulators have been removed within the past five years, Nicor Gas said Wednesday.
"Our primary goal is to give our customers the peace of mind that they deserve," said Nicor CEO Tom Fisher. "We believe that we have been careful over the decades but we want to make sure."
The Naperville-based company had inspected 255 homes by Monday and found higher than normal mercury levels in about one-sixth of them.
Nicor began looking into possible mercury spills on July 20 when the company discovered traces from a liquid mercury spill after a contractor replaced an old gas regulator, which controls the flow of natural gas.
Company inspectors went through homes in 11 suburbs this month, and on Friday it detected mercury in a home where one of its own technicians had removed an outdated regulator.
So far, 322 homes have been inspected, Nicor spokesman Lee Haines said Wednesday. He said there had been some evacuations and cleanups, but he did not know how many.
Illinois Atty. Gen. Jim Ryan said Nicor told his office Tuesday that it could take up to six months to complete the inspections.
Nicor is paying for blood and urine tests, and the Illinois Department of Public Health said Monday that results which had come back so far show only one person out of 10 with an elevated level of mercury.
Mercury, a silver, odorless liquid, has been used in everything from thermometers and blood pressure gauges to older gas meters. Most health experts agree that short exposures to small amounts are relatively harmless -- for example, when a thermometer breaks. The trouble comes, they say, when the liquid vaporizes.