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INDIANAPOLIS. Ind. (June 20, 2015) — Four people were injured when fire destroyed a food truck parked outside a near west side business Saturday afternoon.

Indianapolis fire and medic units were sent to 940 West 16th Street around 3:45 p.m.  The food truck was parked in the parking lot of Pic-A-Part Auto Parts Store.

Two food truck employees were critically burned. One employee refused medical treatment at the scene.  A customer was also burned and is in serious condition.  The three more seriously injured were transported to Eskenazi Hospital.

Fire investigators have ruled the cause of the truck fire to be accidental. Records from the Marion County Health Department show the truck was not licensed to operate in Marion County and was last licensed in 2013. Licenses are issued each year, the agency said, adding that operators must apply for them.

Investigators believe the truck workers turned off the generator to refill it with gas.  When they removed the lid to refill the fuel tank on the generator, gasoline bubbled out.  It is believed fumes from the gas hit the nearby open flame from the propane grill where employees were cooking meat.

Fire officials say the propane grill was working properly but suspect the grill was the flame source that touched off the gas fumes.