A major hurdle for elections officials in at least 17 counties was crossed this afternoon, when Secretary of State Bruce McPherson gave approval for voting machines made by Diebold Elections Systems to be used in the June 6 primary.

Diebold machines– one model optically scan ballots, the other is an electronic touch-screen system– have been in a bit of limbo for weeks, after concerns over security issues prompted McPherson to send the machines back through the federal testing process.

Today’s news release says that process is still incomplete, but that McPherson has received assurances on security issues through a report submitted to him on Tuesday from a team of state investigators who were also looking at Diebold’s operating system.

“After rigourous scrutiny, I have determined that these Diebold systems can be used for the 2006 elections,” said McPherson in a prepared statement.

The decision will no doubt be controversial with many of the critics of electronic voting systems, and McPherson’s decision seems to anticipate that. His statement lays out a set of extra precautions that must be taken by any county using Diebold machines.

Those precautions include extra poll worker training; secure storage of memory cards for the machines; and tamper-proof seals on the machines that must be verified before voting begins on the day of the election.

“We look forward to helping administer successful elections in California,” said Diebold president Dave Byrd in a written statement. Diebold says it plans to have its machines in 21 California counties by June.

Probably most relieved by the decision is San Diego County, where the first big election in the state this year is April 11, to fill the seat vacated by the resignation of U.S. Representative Randy “Duke” Cunningham. San Diego uses the Diebold TSx touch-screen machine, and Registrar of Voters Mikel Haas has jokingly said in recent weeks that the machines were just sitting in a warehouse across town, waiting for clearance.

It looks like he can now go get those devices out of storage.