Optech 4C-400 optical scanners failed to read 21,000 votes on absentee ballots because two lights that read the ballots were worn out.

... Snohomish County was the first jurisdiction to catch the problem, said Sheree Noell, a sales executive for Sequoia.

The problem came to light this winter when the Snohomish County Republican Party pointed out that up to 25 percent fewer votes than voters were counted in some county legislative races. Two recounts showed more than 21,000 votes were missed in the county's legislative races alone, although none of the corrected counts changed the election results.

The Snohomish County Auditor's Office called Sequoia to analyze the machines.