An Ohio Inspector General report in July found that a trooper made copies of an exam he took in 2007 and shared answers with other troopers when he retook the test in April. The test is required for certification to run breath-testing equipment.
The report also found that there was evidence of related cheating by troopers on tests given on four other dates in 2007 and 2008.
Most of the allegations concern troopers or sergeants assigned to the Canton post.
In addition to the 12 recommended for termination, two sergeants are being demoted and three others in the patrol have been reprimanded, said patrol spokesman Lt. Tony Bradshaw.
The cases go before a hearing officer Friday at the patrol's district headquarters in Massillon.
Bradshaw said he could not disclose names of those disciplined pending the hearing.
Herschel Sigall, an attorney for the Ohio State Troopers Association, said in a statement that the union will conduct its own investigation and plans to challenge at least some of the allegations based on lack of evidence of cheating.