State officials are reviewing votes discarded by optical scanning devices.
Minnesota election officials Wednesday began a hand recount of ballots rejected by scanners to determine the winner of its U.S. Senate race between Democrat Al Franken and Republican Sen. Norm Coleman.
Before the recount, Coleman held a lead of about 200 votes, or about 0.5%. The 6,000 ballots rejected by optical scanners could change the outcome of the race.
The Minnesota secretary of state said that the scanners could have rejected two of every 1,000 votes, mostly likely because the ballots were not filled out properly. Three other state races also are subject to recounts.
Minnesota laws allow votes to be counted as long as voter intention is clear, so voters who circled a candidate's name instead of correctly filling in circles next to the names will still have their votes count.
Officials said it could take until the first week of December to complete the recount by hand. It could take until Dec. 16, when the state's canvassing board meets, to determine the results.
Hundreds of officials in 110 locations across the state will determine which ballots are valid. Their work could also include reviewing already rejected absentee ballots, because Franken sued for the names of voters whose absentee ballots were rejected.
Minnesota election officials said the fact that the state can do a hand recount shows that the system works and that the tallies can be audited.