The accident happened along Route 611 (Easton Road) near Tohickon Valley Road.
While the fire is now out, Route 611 remains closed in the area.
The evacuations were ordered in a one mile radius of the scene. That order was lifted by mid-afternoon.
Those evacuated were taken to St. John's Rectory located at 4050 Durham Road in Nockamixon Township. Some were notified by phone, while others learned of it after a knock at the door.
"This morning we had just finished breakfast and we were getting ready to do some 'touristy' things for the day when the knock came on the door for mandatory evacuations, so we grabbed our jackets and left," said Janet Souza.
"Basically we noticed traffic stopped at 8:00, no customers were coming in or anything. All of a sudden, a gentleman from the fire company said 'we're evacuating the area within a mile radius," said Will Ganley of the Ottsville Post Office.
The tanker truck was apparently involved in a crash with a sedan, which was also stopped at the scene. There are two reports of injuries but no word on their conditions.
Police are investigating the cause of the crash.