Glad your co-worker is fine. The fire may have been caused by the Catalytic converter. Here's a little clip about possible dangers with them ...
Car owners have also discovered that a catalytic converter can be a fire hazard. Since 1975, fire departments have found that many automotive fires have been started because a motorist parked a car over dry leaves. Even with the engine turned off a hot catalytic converter can emit sparks (Catalytic converters can get as hot as 1,800 degrees Fahrenheit) which can ignite leaves underneath. Should that unfortunate event happen, your car could be devoured by flames within minutes and destroyed.