SANTA FE, N.M. (AP) — New Mexico credits its reliance on paper ballots in part for making the state less vulnerable to hackers and vote thieves.

The state was not among the 21 states where Russian hackers were accused of targeting voting systems last year, New Mexico election officials said.

As concerns circulate about cybersecurity and the election process, more states are considering turning back to paper ballots, The Santa Fe New Mexican reported Tuesday.

All 33 New Mexico counties use paper ballots after the Legislature passed a law in 2006 requiring physical ballots for any election held under state law. The ballots are counted with electronic scanners, and a paper trail is created that’s stored for nearly two years after most elections.

Secretary of State Maggie Toulouse Oliver said this process makes it more difficult for the outcome of an election to be altered.

Despite the apparent safety of paper ballots, experts said there are still possible ways elections could be tampered with. Other observers warn that states with paper systems should avoid complacency because an election still requires the use of computers in other steps of the process.

“Just because you’re filling in a ballot, don’t be disabused of the notion that technology pervades every other part of the process,” said Joseph Lorenzo Hall, chief technologist of the Center for Democracy and Technology in Washington, D.C.

Some members of the U.S. Congress are pushing for legislation to better alert state election officials of threats to voting systems. U.S. Sen. Martin Heinrich unveiled legislation that would allow the federal government to share certain classified information with state election administrators. The move comes because national security officials did not always know with whom they should share that information, the Democratic senator from New Mexico said.

The bill would extend security clearances to top state election administrators so the federal officials could “be more blunt about what is going on,” Heinrich said. The bill would also provide guidelines to help secure election systems and create grants for states to improve equipment.