ALBUQUERQUE, N.M. (AP) — Another group of workers is suing Los Alamos National Laboratory over its COVID-19 vaccine mandate, arguing that the requirement discriminates against employees who sought religious or medical exemptions.

The complaint was filed Friday in federal court by the Thomas More Society, a Chicago-based law firm, on behalf of eight workers. Under the lab's policy, those with religious exemptions have to use vacation time or go without pay until they are allowed to return to work, and it's up to lab management to determine when it’s safe for them to return.

“This is discrimination, pure and simple,” special counsel Tyler Brooks said Tuesday in a statement. “Los Alamos claims to have offered exemptions for those who have sincere religious reasons for not taking a mandatory COVID vaccine, but their one-size-fits-all so-called ‘accommodation’ is flagrantly illegal. Accommodation by termination has never been a lawful option.”

The lab said Tuesday in a statement that its most important asset is its workforce and that vaccination is the best tool it has to prevent the spread of COVID-19 at the lab, where nearly 99% of workers are vaccinated. However, the lab did not address questions about what protections it might offer its workforce given that state health officials repeatedly have warned that vaccinated people can still become infected and spread the virus.

The latest data from the state Health Department shows 27% of cases reported over the last four weeks have been among vaccinated people. Health officials have said they expect this number to increase as immunity wanes.

An effort by more than 100 engineers, technicians and other workers who sought to put the vaccine mandate on hold was rejected by a state district judge earlier this month, clearing the way for the lab to begin firing workers. Lab Director Thomas Mason told employees during a recent meeting that 185 workers had left over the mandate. About two dozen were granted medical exemptions, and more than 150 were granted religious exemptions.

The lab employs nearly 14,000 people.

The lawsuit argued that the lab refuses to detail its criteria for determining when COVID-19 levels are low enough for employees on leave without pay to return to work.

“Defendants' approach is designed to maximize the uncertainty and anxiety of those employees ready and willing to return to their jobs in an effort to force compliance with their mandate despite recognizing that plaintiffs and others have a bona fide religious exemption to taking the vaccines,” the complaint reads.

Lawyers for the workers said their clients stand to lose professional standing as well as security clearances as a result of the mandate.

The birthplace of the atomic bomb, Los Alamos is one of the nation's premier nuclear weapons facilities. It's under pressure to begin producing key components for the nation's nuclear arsenal and it conducts research on a wide range of topics from public health to energy infrastructure.

The law firm had asked Mason to revisit the vaccine policy but he declined, stating that the policy complied with state and federal laws.

Brooks noted that in Tennessee, a federal judge issued a temporary restraining order against Oak Ridge National Laboratory's vaccine mandate based on similar claims.

Aside from civil rights and constitutional violations, the lawsuit argued that the lab has refused requests for medical accommodations for those workers who have fully recovered from COVID-19 and have natural immunity.

Susan Montoya Bryan, The Associated Press