No one was hurt when more than two dozen cars of a CSX train ran off the tracks around 4:30 a.m.
One of the cars was carrying methanol, but CSX spokesman Gary Sease said there is no indication the car leaked any of the material.
Methanol is used as a solvent, as a pesticide and as alternative fuel, according to the Emergency Response Safety and Health Database, a part of the U.S. Centers for Disease Control and Prevention. It can cause problems ranging from eye irritation to nausea to organ damage, the database said.
Another car carrying propanediol was leaking. The thick liquid is used in laminates and coatings but is not a risk to the public, Fire Chief Mason Speer said.
Hazardous material crews were working to contain the leak, which Speer said could contaminate waterways if it reached a stream.
About a dozen families and several businesses within a few blocks of the derailment will have to stay away for up to three days because of the danger of a possible fire as the rail cars are unloaded and righted, authorities said.
Residents who gathered at the Abbeville Civic Center were allowed to go home as soon as hazardous material crews from the Greenwood Fire Department and Anderson County cleared the area, Speer said. Residents were being encouraged to stay inside Thursday.
The first engine arriving at the scene backed out when firefighters' eyes started burning, Speer said.
A team from the Department of Health and Environmental Control went to the scene to help evaluate what was on the train and the risk it posed.
The train was headed from Atlanta to Hamlet, N.C., Sease said.
Abbeville is a town of about 5,500 people located about 50 miles south of Greenville.