Four people have sued two companies with factories in Lake County, alleging pollution from the sites gave them or family members cancer.

The cases against Vantage Specialty Chemicals in Gurnee and Medline Industries in Waukegan were filed Wednesday in Cook County circuit court. They target the companies' ethylene oxide emissions.

A sterilizing agent for medical equipment and manufacturing industrial chemicals, ethylene oxide is considered hazardous, health officials have said.

Prolonged exposure to the colorless, flammable gas can cause cancers such as leukemia, according to the National Cancer Institute.

There is no safe threshold for it.

Environmental tests have detected the gas near the Medline and Vantage plants, health officials have said.

The lawsuits were filed separately. All four name both companies.

Vantage has a chemical plant in Gurnee and facilities around the world. Medline has a factory in Waukegan but is headquartered in Northfield; it also has offices around the world.

In response to the claims, Medline issued a statement vowing to defend any lawsuits "vigorously."

"We have always operated in compliance with all laws and regulations (and) have always operated at or below our permitted levels," the statement reads.

Representatives of Vantage couldn't be reached for comment Wednesday afternoon.

One plaintiff, Patty Bennett, is a Gurnee resident who was diagnosed with leukemia in 2016, her lawsuit states. She lives about a mile from the Medline factory and about 2 miles from Vantage, the lawsuit states.

A second plaintiff, Gurnee resident Kathleen Koch, was diagnosed with breast cancer in 2014, her complaint states. She reportedly lives less than a mile from the Vantage factory and nearly 4 miles from the Medline plant.

A third plaintiff, Dawn Rex, filed the complaint for her 3-year-old son, Samuel Dolcimascolo. He was diagnosed with leukemia this month, the lawsuit states. They reportedly live in Waukegan, about a mile from Medline and 3 miles from Vantage.

The fourth plaintiff, Gurnee resident Chandra Sefton, was diagnosed with leukemia in 2004, her case states. She formerly lived in Waukegan, too. That former home in Waukegan and a former home in Gurnee were within 4 miles of both factories, her lawsuit states.

The lawsuits accuse Vantage Specialty Chemicals and Medline of negligence and "willful and wanton conduct."

None of the lawsuits identifies a specific amount of damages being sought.

The plaintiffs are represented by two Chicago law firms: Edelson PC and Tomasik Kotin Kasserman.

Similar lawsuits have been filed against Oak Brook-based Sterigenics, whose Willowbrook plant has been blamed for polluting the air with ethylene oxide.

The Illinois EPA shuttered Sterigenics in February, and it remains closed. Similar action has been requested by lawmakers in Lake County.