Zoox grounds Atlanta test fleet after workers report toxic gas exposure symptoms

Zoox halted testing of its modified SUVs in Atlanta after multiple drivers and contractors reported symptoms last month that they and some clinicians linked to exposure to gases such as carbon monoxide, carbon dioxide, or hydrogen sulfide. The episodes continued through much of August and culminated on August 22, when someone called 911 for a sick worker. One contractor, who later filed a complaint with the Occupational Safety and Health Administration, said crews were sent back into vehicles after reporting vomiting and other symptoms.

OSHA viewed by TechCrunch told Zoox the agency believed up to 40 people may have been exposed, though Zoox reported a lower count. In a letter to OSHA, Zoox said it identified 28 employees who had ridden in six test vehicles reporting an “unexplained odor” and that 10 workers voluntarily underwent medical evaluation; the company received one medical report noting carbon dioxide exposure. Zoox said it has not detected carbon monoxide in its vehicles.

As part of its response, Zoox said it examined exhaust systems, conducted smoke tests for cabin intrusions, removed and inspected 12-volt batteries, and replaced them. The company told OSHA it detected only carbon dioxide in the impacted vehicles and plans to install CO2 monitors that the company says will also be capable of detecting gases such as carbon monoxide and hydrogen sulfide. After informing OSHA of its findings, the company paused operations of its Atlanta test vehicles while it continued its investigation.

Workers described smells and symptoms consistent with hydrogen sulfide to TechCrunch, and Zoox noted damaged 12-volt batteries can produce hydrogen sulfide and a “rotten egg” odor; Zoox later told TechCrunch it had detected no battery damage and no signs of hydrogen sulfide. Zoox also emphasized that its purpose-built electric robotaxis are not affected and said it consulted an outside medical expert during the probe.

The incidents come as Zoox expands testing into additional cities. TechCrunch previously reported injuries to contractors from sudden braking and swerving in Zoox test vehicles; Waymo has also reported similar test-driver injuries to OSHA. The company said its priority is the safety and well-being of its test fleet operators and that it is taking “appropriate, and cautious actions” while investigating the reported events.