By Dave Savini

CHICAGO (CBS) — Five women who worked at a high school in Illinois said emissions from a nearby sterilizing plant caused them to develop cancer.

They filed a lawsuit against Sterigenics, the company that operated the plant.

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For over 30 years, Sterigenics sterilized medical equipment at its facility in Willowbrook, near Chicago, using a gas called ethylene oxide, a chemical known to cause cancer.

Unknown to residents and the teachers at Hinsdale South High School, the plant released thousands of pounds of the invisible gas into the surrounding neighborhoods for decades, CBS News consumer investigative correspondent Anna Werner reports.

“Many of us taught with our windows wide open in the spring, in the fall,” former teacher Peg Vahldieck said.

She and former educators Margaret Eskey Erdmanis, Rose Keppler, Carol Tufo and Jeannie Debroeck all said they had never heard of ethylene oxide. They all have cancer.

Over the years, they started noticing the number of their former colleagues who came down with cancer.

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“There were five in the wing that I worked in,” said Erdmanis, who has terminal blood cancer.

“In my department, there’s six of us,” added Debroeck, who has breast cancer.

Tufo, who also has breast cancer, said the teachers used to tell each other not to drink the water at the school because “we needed a reason for why people were sick.”

CLICK HERE FOR CBS 2’S COMPLETE COVERAGE OF STERIGENICS AND THOSE AFFECTED BY THE PLANT’S EMISSIONS

Ethylene oxide is used to sterilize about half of all U.S. medical equipment in plants around the country. Experts have known for decades that the toxic gas could be linked to cancers including breast and blood cancers.

But it wasn’t until last year that residents in nearly 20 communities around the country found out that by a new EPA analysis, their cancer risk from exposure to the chemical might now be higher.

The Sterigenics plant in Willowbrook, less than a mile from the high school, became a flashpoint for protests, bringing awareness and anger.

“I am as mad as can be,” Tufo said. “I’m worried about the people that do not know. They need to know your health is at risk.”

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“It’s not only a local issue,” added Vahldieck. “It’s a national issue, and people are unknowingly being exposed without having to be.”

Sterigenics now faces multiple lawsuits, but the company told CBS News in a statement that it’s “confident that it is not responsible for causing” cancers and that it has “consistently complied with and outperformed applicable regulations.”

Lawyer Shawn Collins, who represents the five women, insists the company knew there were risks. He pointed to a letter from the Illinois EPA to the plant’s former owner in 1984, warning that when its sterilizers were built, ethylene oxide emissions could be “several magnitudes higher than desirable.”

“I’ve never seen a situation where before a company even opened its doors it was told, ‘If you do what you say you want to do, you’re really risking the health of your neighbors,’ and then it went ahead and did it anyway,” Collins said.

Sterigenics closed its Willowbrook plant in September, citing problems with a lease. But nationwide, more than 100 sterilizing plants still use ethylene oxide.

The Sterigenics story is one that Dave Savini and the CBS 2 Investigators have been covering all year long. Savini introduced us to several people who’ve gotten seriously ill, including children who live nearby.

Sterigenics maintains it is not responsible for causing anyone’s illness, calling the lawsuits quote “unfounded and meritless claims.”

Its Willowbrook plaint has since shut down.

In a statement, Sterigenics said:

“Sterigenics empathizes with anyone battling cancer.  Sterigenics is confident that it is not responsible for causing the illness.  We operate safely to sterilize vital medical products and have consistently complied with and outperformed applicable regulations. We intend to vigorously defend against unfounded and meritless claims.”

Dave Savini’s reporting led to the passing of a new law in memory of Matt Haller who died of stomach cancer, an illness he blamed on Sterigenics. The Matt Haller Act requires facilities to limit emissions of ethylene oxide by 99.9%.

To see Savini’s previous reports that led to this change in law, go to cbschicago.com/sterigenics.

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