FULTON, Mo. -- State Sen. Chuck Graham pleaded guilty Friday to driving while intoxicated.

Graham, who appeared before Associate Circuit Judge Carol England in Fulton, was fined $500 and ordered to pay $122 in court costs on the misdemeanor DWI charge. He could have received as much as six months in jail on the charge.

"I once again apologize to my friends, supporters, constituents and the other people involved in this incident," Graham said in a statement. "I made a tremendous error in judgment, and it won't happen again. I have learned a valuable and life-altering lesson, and I know I will be a better person because of it."

Graham, D-Columbia, was arrested Oct. 20 after his Chevrolet Monte Carlo rear-ended a vehicle at a stop sign and pushed it into a third vehicle. The other motorists were not injured, but Graham suffered bruises.

Afterward, Graham denied drinking alcohol, according to a police report. He then admitted having had a "few drinks" during the last two hours. Later, he said he had drunk two beers.

Police said Graham, who was paralyzed after a car wreck as a young man and uses a wheelchair, refused six requests to take a breath test. They said he also would not provide a blood sample at the hospital, where he was taken after complaining that his arm was in pain.

A police officer seized a container of Graham's urine at the hospital, and a sample of Graham's blood was taken later after police obtained a court order.

Graham could lose his driver's license for a year for refusing the breath test. He is challenging the automatic suspension. A hearing is set for Jan. 10 in Boone County.