Zoox Grounds Atlanta Autonomous Test Fleet After Toxic Gas Symptoms
Zoox halts Atlanta autonomous SUV tests after up to 40 workers reported illness, while an OSHA inquiry finds only confirmed carbon dioxide exposure in cars.
Summary
Amazon-owned Zoox grounded and quarantined its combustion-engine Toyota Highlander test fleet in Atlanta, and has run its depot at limited capacity since an August 22 911 call for a sick contractor. Symptoms and unusual odors began in early August; OSHA said as many as 40 workers may have encountered carbon monoxide, carbon dioxide or hydrogen sulfide, while Zoox counted 28 employees across six vehicles. On August 14, HireArt contractor Jay Davis and three colleagues became lightheaded, one vomited, and Zoox towed their SUV, then returned them to work in another vehicle where symptoms recurred. Three went to an emergency room; Davis had no elevated carbon monoxide, although clinicians said symptoms were consistent with exposure. The four later received purportedly random drug tests. Davis complained to OSHA, which opened an inquiry and directed Zoox to investigate.
In a September 10 letter, Zoox said 10 workers sought evaluation, with one report identifying CO2 exposure; an expert assisted, no carbon monoxide was identified, and CO2 was the only gas detected. Zoox tested exhaust and cabin sealing without disclosing results, replaced all 12 volt batteries without saying whether damage was found, and will add CO2 monitors; damaged batteries can emit hydrogen sulfide, matching rotten-egg odors. OSHA closed its inquiry, but Atlanta testing remains halted as of September 23, 2026. Zoox says ventilation is unmodified, although the SUVs carry autonomy hardware and an interior air snorkel, run much of the day, and use depot exhaust capture. Its electric purpose-built robotaxis are unaffected. Expansion in Las Vegas and San Francisco against Waymo follows contractor injuries from sudden braking and swerving; Waymo reported similar injuries. Zoox is an outlier using combustion test vehicles versus electric fleets at Waymo, Tesla, Avride and Motional; May Mobility has hybrids, while Nvidia runs gas and electric Mercedes-Benz sedans.
Positives
- Zoox quarantined its Atlanta test vehicles and halted operations while investigating the reported exposures.
- Ten workers underwent medical evaluation, and Zoox consulted an outside medical expert during its investigation.
- CO2 monitors will be added after Zoox detected carbon dioxide in affected vehicles.
- All 12 volt batteries were inspected and replaced, addressing a potential source of hydrogen sulfide.
- Zoox’s all-electric, purpose-built robotaxis are unaffected by the Atlanta test fleet shutdown.
Risks & concerns
- OSHA estimated that as many as 40 Atlanta workers may have encountered carbon monoxide, carbon dioxide or hydrogen sulfide.
- Four workers reporting illness on August 14 were returned to the field, where symptoms recurred in a second vehicle.
- Zoox has not disclosed whether exhaust, cabin-sealing or battery inspections found defects that could explain the incidents.
- Atlanta testing remains suspended, potentially complicating Zoox’s expansion against Waymo in Las Vegas and San Francisco.
- Zoox’s combustion-engine test SUVs introduce exhaust risks absent from the electric fleets used by several major robotaxi rivals.
- Contractors have also suffered injuries from sudden braking and swerving in Zoox test vehicles.