The 2002 Ford F-150 is among 1.1 million pickups targeted for recall due to a potential fire risk.

Ford is recalling more than a million full-size pickups in the U.S. and Canada due to a possible fire risk.  But federal regulators are continuing to investigate and may add another 1.6 million more trucks to the recall list.

The National Highway Traffic Safety Administration upgraded its investigation into the problem, in May, after receiving 243 reports involving fuel tank problems that could lead to a leak and fire.

“Our investigation is still open until NHTSA can fully evaluate the steps Ford has taken today,” said NHTSA spokeswoman Lynda Tran.

Those steps include the recall of 1.1 million pickups produced between 1997 and 2004.  An additional 120,000 face recall in Canada.  The affected vehicles include F-150 pickups built between 1997 and 2003, as well as the 2004 F-150 Heritage model.  Also on the list: 1997 to 1999 F-250 models weighing in under 8,500 pounds, as well as the 2002-03 Lincoln Blackwood pickup.

The vehicles were sold in 21 states, as well as the District of Columbia, where Ford says the potential for rust problems could lead fuel tank straps to break, allowing the tanks to drop and scrape on the ground.  It is possible that could, in turn to a leak and fire, especially if the tank creates sparks while dragging.

Of the 243 reports collected by the NHTSA, 95 involved fuel leakage and nine resulted in sparking.  Government investigators have received one report of a fuel tank fire that self-extinguished, but Ford acknowledges it also received a report of a fire that resulted in a vehicle being destroyed.

The recall involves trucks that were sold in or are currently registered in: Delaware, Connecticut, Delaware, Illinois, Indiana, Iowa, Kentucky, Maine, Maryland, Michigan, Massachusetts, Minnesota, Missouri, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, West Virginia and Wisconsin.

The latest recall alone involves about twice as many vehicles as Ford recalled in the U.S. for all of 2010.  But the maker has already called back another 2 million cars and trucks for a variety of issues including excess corrosion and faulty tires.  In April, the Detroit maker expanded an ongoing recall involving faulty F-Series pickup airbags.  So far, that recall has involved 1.3 million vehicles.