TUOLUMNE COUNTY (CBS13) – Authorities say a busted catalytic converter started a series of small wildfires in rural Tuolumne County on Thursday.

The melted pieces as found in the field. (Credit: Cal Fire)

READ MORE: Home And Sheds Catch Fire In Del Paso Heights

Cal Fire’s Tuolumne-Calaveras Unit says firefighters responded to a total of seven small fires along Tuolumne Road, near Morris Avenue, that afternoon.

READ MORE: SunVilla Solar Patio Umbrellas Sold At Costco Recalled After Multiple Fires

Crews were able to contain the flames within a half hour.

An investigation into what started the fires revealed something alarming – that melted and ejected pieces from a catalytic converter were to be blame.

MORE NEWS: Search Histories, Location Data, Text Messages: How Personal Data Could Be Used To Enforce Anti-abortion Laws

Notably, Cal Fire says the vehicle that caused the fire is still a hazard. Anyone who may have seen a vehicle experiencing mechanical difficulties in the area just before the fires is urged to call investigators at (209) 754-3831.