MOUNT PROSPECT, Ill. -- A suburban school bus driver is accused of driving dozens of students home from school with a high blood alcohol level.

The Cook County state's attorney's office says 54-year-old Betty Burden of Mount Prospect admitted downing several vodka drinks before driving 50 students from Lions Park Elementary School.

Prosecutors say Burden's blood alcohol level was 0.226 percent.

The legal limit in Illinois is 0.08 for regular drivers and 0.04 for drivers with a commercial driver's license.

But a spokeswoman for the secretary of state's office says Illinois has a zero-tolerance policy for school bus drivers.

State officials say Burden has been a school bus driver since 1991.

Burden couldn't be reached for comment. She doesn't have a listed phone number, and it isn't clear if she has an attorney.