A suburban Chicago contractor has pleaded guilty to setting a fire at a radar facility that disrupted air traffic throughout the country.

Brian Howard entered the plea Thursday in federal court in Chicago. Prosecutors told the judge Howard may be responsible for more than $100 million in restitution. According to a plea agreement, Howard will face at least a mandatory decade in prison.

Defense attorney Ronald Safer previously said the goal was for Howard to serve his time in a federal prison offering mental health treatment.

The 37-year-old Naperville man was a contract employee at the Aurora facility in September when authorities say he cut cables and set fire to a telecommunications room. The resulting blaze forced O'Hare and Midway airports to close.

The judge set sentencing for Sept. 11.