San Antonio Police called out the fire department and the bomb squad following a routine traffic stop overnight, News Radio 1200 WOAI reports.
When officers pulled over the SUV in the 1700 block of Jackson-Keller, which is not far from LEE High School, an officer discovered a propane tank in the back with a flare attached.
The Fire Department was called and the area was cleared. Eventually, the bomb squad determined that there was no danger from the device because there was no ignition device attached to the fuel tank.
There's still no word on why the man had the device in his car. He was taken into custody by officers.