Twenty-four Amazon workers were hospitalized after a bear spray was chopped into a warehouse in New Jersey in the United States on Wednesday.
One of those hospitalized is in a critical condition. Other 30 people were treated with emergency services at the scene.
Not clear what caused the accident, but Amazon is exploring.
Workers evacuated the third floor of the south entrance to the warehouse during the event on Wednesday morning.
Workers experienced breathing problems, and spinning in their throats and eyes, local officials said.
John Nalbone, spokesman for Robinsville Township, told the BBC that there was no threat to residents in the region and that smoke was limited to within the building.
Operations at the 1.3m square installations – which work more than 3,000 people – since then they have resumed normal, added Mr. Nalbone.
"The security of our employees is always our highest priority and complete research already in the way," said Rachael Lighty, Amazon spokeswoman.
According to the Get Bear Smart Society, the non-lethal bear-repeller causes "almost total, still temporary, loss of sight and severe limitation of breathing" in bears and humans.