Two litres of chemical waste is thought to have been spilled in the accident, and is currently being attended to in Fife.
The waste which is an agricultural seed treatment is “not hazardous” but emergency services are treating it as a chemical spill.
Emergency services were called to the scene at 7.59am when the tractor and trailer overturned on the main road roundabout in Leuchars.
The driver was carrying a chemical which is used to prevent the spread of disease in crops.
Though not a hazardous chemical, it can be potentially poisonous if mishandled or misused.
Some seed treatments are toxic and a chemical respirator and goggles should always be worn when handling it.
A spokesman for Fife Fire and Rescue Service said that the driver of the vehicle was not injured in the accident and that the spillage has been contained however.
He added: “There is a recovery vehicle attempting to right the trailer to investigate further spillage but so far it has been contained.
“It is not particularly hazardous but is being treated as chemical. It is a pollutant and can be hazardous if it comes into contact with skin or eyes.
“We also need to prevent it from entering into the water system.”
Two fire engines from St Andrews and three from Methil were called to the scene as well as the ambulance service and Fife police.