Ford Motor Co. is recalling more than 1 million trucks, including the F-150, the top-selling U.S. vehicle, because straps that secure fuel tanks to the vehicles may corrode and cause the tanks to fall.

The defect has led to three fires and one injury, Wesley Sherwood, a Ford spokesman, said in an e-mail. The National Highway Traffic Safety Administration announced the recall today on its website, reported Bloomberg.

The recalls follow an investigation opened last year by the U.S. auto-safety regulator. They are made in 21 U.S. states, and the District of Columbia, where de-icing chemicals used on roads in cold weather may cause corrosion of the metal straps.

“Ford has been polishing their image and getting it very, very good, so this doesn’t help,” said Jim Hall, principal of 2953 Analytics Inc., a consulting firm in Birmingham, Michigan. “They’ve got to get ahold of the affected customers fast; get it handled and put to bed. Don’t let it linger.”

The trucks being recalled are “older, higher-mileage” vehicles and have fuel-tank straps that “can corrode after operation for extended periods of time in high-corrosion areas,” Sherwood said.

Ford, based in Dearborn, Michigan, said the recall covers 1.1 million pickup trucks, including F-150s from model years 1997 to 2004; F-250s from model years 1997 to 1999; and Lincoln Blackwoods from model years 2002 to 2003.

The company said it will notify owners of affected vehicles in mid-September and make repairs at no cost. If replacement straps aren’t available when the recall repairs are done, the company said it may install a cable support under the fuel-tank strap as an interim repair.

Ford earlier this year recalled more than 1 million F-150s for air-bag defects after a push by U.S. regulators. Air bags in trucks from model years 2004 to 2006 may not deploy when needed. None of the trucks were included in both recalls, Sherwood said.

Ford rose 14 cents, or 1.2 percent, to $12.35 at 4:02 p.m. U.S. East Coast time in New York Stock Exchange composite trading. The shares have lost 26 percent this year.