BOULDER, Colo. — The American Civil Liberties Union of Colorado filed a lawsuit Aug. 3 in federal court over the Boulder County jail’s policy of restricting inmates’ outgoing mail to postcards.

The ACLU claims the policy is unconstitutional because inmates are reluctant to freely express themselves and write about personal, sensitive information. Mark Silverstein, the Colorado ACLU’s legal director, said the policy also violates the First Amendment rights of the recipients and possibly the news media, which might receive tips from inmates.

“This unnecessarily infringes on the rights of hundreds and hundreds of prisoners and potentially thousands of their correspondents in the outside world,” Silverstein said.

Boulder’s policy is rarely used by other jails, Silverstein added.

Boulder County Sheriff Joe Pelle said the practice is used by jails in Arizona and Oregon and has been upheld by federal courts. He said Boulder County had received calls about it from in- and out-of-state agencies.

The El Paso County sheriff’s department recently approved a similar policy. Sheriff Terry Maketa told The Gazette in Colorado Springs that the change was made to be more efficient. Using postcards will save $5,000 yearly, he added.

Silverstein said the ACLU had requested information about El Paso County’s new system.

Boulder County began looking at how other jails handled mail after two sex offenders sent Boulder-area children letters in envelopes that were stuffed inside envelopes addressed to a third party, who forwarded the letters. The policy was adopted in March.

“The difficulty we have is in our jail, we handle 1,000 pieces of outgoing mail a day,” Pelle said. “It’s not possible to check each piece.”

Pelle called the mail restrictions a balancing act between protecting inmates’ rights and keeping the public safe. Inmates can ask to send medical and legal information in private letters and can speak privately in telephone calls or visits at the jail, he said.

Silverstein said the policy is an overreaction. He said the jail could come up with different solutions, such as prohibiting envelopes inside other envelopes.

Silverstein also questioned Boulder County’s argument that restricting inmates’ mail would withstand a legal challenge. He said prisoners pursuing similar cases didn’t have attorneys.