A dentist who worked in two Colorado prisons claimed in a new whistleblower lawsuit that he was fired after raising concerns about the state Department of Corrections’ continued use of tooth fillings that contain mercury.
Dentist Charles Hardin was fired April 4, hours after he emailed the DOC’s chief of dentistry, a registered nurse and a psychologist to suggest the prison system change its approach to such fillings to align with federal recommendations, he alleges in the lawsuit filed last week in Denver District Court.
Hardin, who became a contracted dentist for the DOC in late 2023, primarily worked in La Vista Correctional Facility, a women’s prison, and San Carlos Correctional Facility, a prison with a specialized population of inmates who have complex medical needs. Both prisons are located in Pueblo.
Hardin grew concerned that the prison system’s default approach to dental treatment was to use mercury amalgam, which is a mix of mercury and other metals, for dental procedures like fillings. The U.S. Food and Drug Administration in 2020 warned that mercury fillings posed a risk of harm to particular patients, including pregnant and nursing people, people who want to become pregnant in the future and people with some pre-existing medical conditions.
The FDA found that mercury-containing fillings, which have been commonly used for more than a century, released small amounts of mercury vapor over time with regular wear and tear, and that while the vapors are typically not harmful, they can cause problems in high-risk patients.
Hardin grew concerned that the prison system was over-relying on mercury amalgam when “safer alternative materials existed,” and when at-risk or mentally ill prisoners could not knowingly consent to the mercury mix’s risks, according to the lawsuit.
“The closed and institutional environment of a correctional facility further heightens these concerns because inmate-patients have limited access to outside dental care, limited ability to choose alternative restorative materials, and often lack the necessary clinical monitoring or diagnostic testing to identify or manage potential mercury exposure,” the lawsuit states.
A spokeswoman for the Colorado Department of Corrections, Alondra Gonzalez, did not return a request for comment Tuesday.
Hardin emailed Michael Hale, chief of dentistry for the correctional department, on April 4 about his concerns.
“I am concerned with how CDOC… mandate(s) that I violate current FDA guidelines concerning dental material selection,” he wrote in the email at 1 p.m. that was included in the lawsuit. “I would like some guidance on if I should adhere to the CDOC regulations… and go against the current FDA regulations.”
He was fired at 5:58 p.m. the same day, the lawsuit alleges. The contract company he worked for told him that that prison officials felt he was not “a good fit for them,” according to the complaint.
One of Hardin’s attorneys, Michael Kuhn, said Tuesday that Hardin did not have any warning that he was about to be fired, and noted that one colleague emailed him the day before he was fired and said she expected to see him at work “next week.”
“He had raised certain safety concerns in the past, and I don’t think they were well-received,” Kuhn said. “This may have just been the tipping point when he sends this. He sends this email and he is gone within a matter of hours.”
The lawsuit accuses the Department of Corrections of violating the state’s Public Health Emergency Whistleblower Act, which prohibits employers from retaliating against workers who raise workplace health and safety concerns in good faith. Hardin is seeking back pay, reinstatement, financial damages and other relief.
“It’s just to hold the Department of Corrections accountable for the wrongful termination,” Kuhn said. “And we do think that the CDOC should absolutely change the policy to protect the vulnerable population.”
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