A lawsuit has been filed against a medical equipment distribution center in Lithia Springs and a controversial medical sterilization plant in Cobb County for allegedly exposing the warehouse employees to unsafe levels of a carcinogenic chemical over a decade.

There are 53 plaintiffs who either worked or whose relatives worked at the distribution center, where they were allegedly exposed to ethylene oxide.

The complaint claims that multiple people died or became seriously ill as a result. The suit was filed in Cobb State Court this week and names as defendants Sterigenics, the sterilizer; its parent company, Sotera Health; the ConMed Corporation, which operates the distribution warehouse; as well as several managers associated with both companies.

Sterigenics operates one of a handful of facilities across the state permitted to use ethylene oxide to sterilize medical equipment.

Recently, these companies have come under scrutiny after the federal government concluded ethylene oxide was much more toxic than previously thought, and may increase risk of cancer in surrounding neighborhoods after years of exposure.

The lawsuit alleges Sterigenics failed to follow safe aeration procedures by prematurely shipping sterilized items saturated with ethylene oxide “in unmarked and non-equipped trucks” to the warehouse, where unsuspecting workers unloaded them. It also accuses ConMed of failing to protect employees from ethylene oxide and lying to them about their exposure and risk.

ConMed did not respond to a request for comment.

In a statement, Sterigenics said neither it nor its employees caused injury to the plaintiffs.

“The allegations asserted in this lawsuit against Sotera Health, Sterigenics and Sterigenics’ employees are baseless, and we will vigorously defend against them,” the statement said. “The plaintiffs are not Sterigenics employees. They are employed by another company and their claims relate to that company’s processes and the work those employees perform at that company’s facility.”

Last year, ConMed was cited for a series of “serious” violations by the labor department and fined more than $13,000 for exposing workers to elevated levels of ethylene oxide, failing to notify employees of their exposure and lacking safety protocols, according to documents provided by the plaintiff’s attorney and the OSHA website. The company later reached a settlement with the agency, the terms of which were not immediately available Wednesday.

After employees learned they had been unwittingly exposed to high levels of ethylene oxide, ConMed “encouraged a private physician who consulted by way of Skype with individual Plaintiffs who were accompanied by a ConMed consultant, to reassure the Plaintiffs that they had nothing to worry about regarding exposure to Ethylene Oxide in the facility,” according to the complaint. It says the company did this “with fraudulent intent and a total disregard for the consequences of their actions.”

The lawsuit alleges ConMed also misrepresented the level and duration of the exposure to employees’ healthcare providers when they sought treatment, and tampered with ethylene oxide detection monitors to fraudulently manipulate the readings.

“The lawsuit filed today seeks to hold Sterigenics and ConMed liable to the 53 injured victims for exposing them to large quantities of Ethylene Oxide gas over a long period of time without their knowledge or consent and concealing the existence and danger of Ethylene Oxide,” Eric J. Hertz, the lead attorney for the plaintiffs, said in a statement. “Workers who serve as key links in the chain to getting much needed sterilized medical equipment to hospitals and patients must not be sacrificed in the process.”

Sterigenics recently resumed operations at its plant near Smyrna, pending the outcome of an unrelated, ongoing legal dispute with Cobb County over its permitting.