Four San Jose garbage trucks caught fire in a single month, with the most recent on July 16 — the San Jose Fire Department attributes each case to improperly discarded lithium-ion batteries being crushed in compactors.

Four San Jose garbage trucks caught fire in a single month, with the most recent blaze on July 16 — and the San Jose Fire Department attributes each case to improperly discarded lithium-ion batteries, NBC Bay Area reported July 17.

When a truck's compactor crushes a battery, it can short, spark, and ignite surrounding waste. Drivers have no option but to dump the load onto the street so firefighters can reach it.

"We know when lithium batteries are crushed or damaged, they can release sparks which can ignite materials around them, which then when they're placed in the collection trucks can ignite the materials and cause fires," Judy Erlandson, Deputy Director of Integrated Waste Management for the City of San Jose, told NBC Bay Area. Republic Services, the city's contracted hauler, operates the trucks involved.

The city's position: no battery — lithium-ion or otherwise — belongs in a trash or recycling bin. The Santa Clara County Household Hazardous Waste Program accepts them by free appointment at hhw.org; the SJFD's standing public education page also instructs residents to call 9-1-1 if a battery begins swelling, heating, or leaking near flammables.

The SJFD has not issued a formal incident report or press advisory for any of the four fires as of July 18. Exact dates and locations for each incident remain undisclosed. The fire count and battery attribution both come from NBC Bay Area's reporting; no independent confirmation from the department's public information office has been obtained.