Prompted by a Tribune investigation that revealed the village's secret use of its tainted well, the Illinois Department of Public Health looked at cancer cases in Crestwood between 1994 and 2006 and found higher-than-expected cases of kidney cancer in men, lung cancer in men and women, and gastrointestinal cancer in men.
As with nearly all studies of cancer clusters across the nation, specific causes are difficult, if not impossible, to determine. But the Crestwood situation is still different than most other cancer investigations.
"We are dealing with a situation where we have known exposure," said Ken Runkle, a state health department toxicologist. "That means we can view these elevated cancer levels in a different light."
Kidney cancer in particular is associated with exposure to perchloroethylene, also known as PCE or perc, a common dry-cleaning solvent that years ago leached into Crestwood's well. Research also links lung and some types of gastrointestinal cancer to perc and related chemicals, which state officials first detected in the well water in 1985.
Crestwood officials avoided scrutiny for years by telling residents and regulators that the village relied exclusively on treated Lake Michigan water. But records show they kept using the polluted well for up to 20 percent of the drinking water pumped to residents.
The well wasn't shut off for good until late 2007, after state officials tested the water again and found it was contaminated with two perc-related chemicals. One of those compounds, vinyl chloride, is a known carcinogen so toxic that the U.S. Environmental Protection Agency says there is no safe level of exposure.
In response to the Tribune investigation, U.S. Sen. Dick Durbin, D-Ill., and U.S. Rep. Bobby Rush, D-Ill., urged federal and state health officials to take a closer look at Crestwood. Gov. Pat Quinn also demanded an investigation as part of a broader effort to ensure that citizens get more information about water contamination in their communities.
Tiefu Shen, a state epidemiologist who oversaw the report, said assessing cancer cases was complicated, in part because Crestwood shares a ZIP code with neighboring Midlothian, people moved in and out of town, and records weren't available to determine how much contaminated water residents ingested over the years.
Shen's group ended up pinpointing Crestwood-specific cases from the Illinois Cancer Registry and found 952 that could be grouped by age, sex, race and cancer type. Those numbers were compared with similar figures for Cook County and the state as a whole.
Researchers found 23 kidney cancers in men when 12 were expected, 63 colorectal cancers in men when 45 were expected and 12 cases of esophageal cancer in men when 6 were expected. With lung cancer, there were 89 cases in women when 66 were expected, and 79 cases in men when 59 were expected.
There were no cases of angiosarcoma, a liver cancer linked to vinyl chloride exposure. But the finding wasn't surprising because that type of cancer is extremely rare and typically is related to workplace exposure, state officials said.
The number of other liver cancers was higher than expected but not statistically significant, according to the report. Childhood cancers were lower than expected.
Many Crestwood residents have been clamoring for answers since finding out they drank polluted water for years. The new state study can't say what caused a specific incidence of cancer, but it highlights some statistical anomalies that can't be easily explained.
"This is what we've been asking for," said Steven Nelson, a Crestwood resident who helped organize a Facebook group to spread information about the contaminated well. "What's been missing is the hard data about any illnesses in the community."
Several residents interviewed Friday said they were concerned the state's findings could mark the beginning of a disturbing trend. Citing the long latency of many chemically related cancers at least 10 years can lapse after exposure before cancer is detected researchers urged continued study in Crestwood.
"I can't help but wonder if what happened to me had something to do with the water," said Frank Caldario, who has lived in Crestwood since 1993 and was diagnosed with kidney cancer last year at age 29.
Caldario, an office worker who doesn't smoke, said surgeons removed a gumball-sized tumor and about 40 percent of his right kidney. Early detection meant he was able to avoid radiation or chemotherapy.