ANNAPOLIS -- A muffled explosion near an underground fuel tank at an Exxon station on Defense Highway near U.S. 50 yesterday evening caused several customers and employees of a nearby toy store to be evacuated, said an Anne Arundel County fire official.

Fire Department Battalion Chief Gary Sheckells said the driver of a tanker truck was about to fill underground tanks with gasoline at Chesapeake Exxon shortly after 8 p.m. when a muffled explosion occurred.

The incident, said Chief Sheckells, resulted in a flame about three feet long erupting into the air. The force blew a metal cover plate several feet. No injuries were reported.

Firefighters sprayed foam and water into the tank, preventing any further incidents.

However, as a precaution, employees and customers at a nearby Toys R Us store were evacuated and sent to the nearby Annapolis Mall while firefighters investigated the cause of the explosion. Chief Sheckells said a motor next to an underground vault containing the fuel tank apparently short-circuited, causing fuel vapors that naturally escape into the atmosphere to "explode."