An atheist group has filed a brief with an appeals court in the United States, asking it to declare religious exemptions for retirement plans unconstitutional.

The Freedom From Religion Foundation (FFRF) submitted its brief to the 10th U.S. Circuit Court of Appeals in Denver, Colorado, which is handling a case on Medina v. Catholic Health Initiatives (CHI).

Janeen Medina, a former CHI employee, filed the case against CHI, saying that the latter should not be exempted from the Employment Retirement Income Security Act (ERISA).

Under ERISA, retirement plans managed by churches are exempted from requirements such as paying insurance premiums, meeting minimum funding standards, and disclosing funding levels to plan participants, the FFRF said.

In a ruling last December, U.S. District Court Judge Robert Blackburn ruled that "I therefore ultimately find and conclude that the CHI plan is properly classified as a church plan and thus is entitled to the benefit of ERISA exemptions for such plans."

In its brief, FFRF is asking the court to go much further.

"Rather than attempt to draw a black line in a black sea, this court can take a clearer path, one that follows a line between black and white," FFRF staff attorney Andrew Seidel wrote in the brief submitted on June 29. "To do so, the court must take a step back and look at the entire picture: The church plan exemption is unconstitutional."

It said the exemption given to church plans violates the Establishment Clause of the First Amendment and that imposing the same requirements on religious plans as for all others would not be an excessive entanglement of government and religion.

The FFRF said in the absence of adequate regulation, church plans are deficient as vast majority of such plans are underfunded with 90 percent in critical status.

It accused churches of taking advantage of their exemption from disclosure requirements.

"Churches are enjoying several privileges over their secular counterparts when it comes to these pension plans," says FFRF co-president Annie Laurie Gaylor. "Courts need to take a close, hard look at the heart of the matter: how this exemption contravenes the First Amendment."

But in his ruling, Blackburn declared that churches' exemption does not violate the First Amendment.

"Accordingly, affording CHI the benefit of the church plan exemption works no violation of the First Amendment," he ruled.