A septic truck went over an embankment on Waterfall Way, five kilometres north of little North Arm Rd, Thora shortly before 3pm Monday afternoon.
A 57-year-old driver was able to remove himself from the vehicle. He sustained mild facial injuries.
The truck was leaking sewage into the national park at a rate of two litres per minute until it was winched clear.
Police, paramedics, SES, Bellingen Shire Council, and both Dorrigo and Bellingen fire station personnel attended.
The Bellingen Shire Courier-Sun requested details of accidents on Waterfall Way this year.
A NSW Transport spokesperson said: “Provisional crash data shows there were no reported fatal crashes this year on Waterfall Way east from the Pacific Highway at Raleigh to the New England Highway at Armidale. Injury and tow away crash data is not yet available”.