The San Francisco International Airport could extend a contract Tuesday with a bus company that provides shuttle service for the hub’s employees and long-term passengers.

The contract agreement, worth $8.1 million, would be a one-year extension with SFO Shuttle Bus Company. If approved, it would mark the fourth straight year airport officials agreed to extend service on a one-year basis with the company.

On Tuesday, the San Francisco International Airport Commission will vote on whether to extend the contract, which would run from Jan. 1, 2011, to the end of that year.

wreisman@sfexaminer.com