BRIDGEPORT - An apparent sickout by Greater Bridgeport Transit drivers crippled bus service Thursday, and Friday will see more route cancellations.

All suburban bus routes were suspended Thursday and remaining routes were on limited schedules. Forty of 72 bus drivers called out sick, according to Greater Bridgeport Transit CEO Doug Holcomb. As of Thursday evening, GBT canceled seven bus routes for Friday and others will run on a limited schedule. Customers are advised to continue checking GBT for updates on Friday’s service.

“We didn’t know this until it started creeping up late last night and then into the morning,” says Holcomb. "It's a stunning blow to the operation."

Some drivers told News 12 Connecticut off camera that the apparent sickout is a protest over pay and working conditions. GBT and drivers have been negotiating a new contract since January.  It's set to go to arbitration this fall.

“We didn't orchestrate it,” says Mustafa Salahuddin, of the Amalgamated Transit Union. “We didn't condone it, and we wouldn't support anything like that. They are sick of their working conditions, and they are sick of the fact that they have to deal with these tight schedules."