(Natural News) An unfortunate "robot mishap" was behind a bear repellant spray incident at an Amazon warehouse that sent dozens of workers to the hospital.

The accident comes at a time when many Amazon warehouse workers are already on edge as they see robots increasingly taking over their tasks and threatening their jobs, and now they have a whole new reason to be wary of the machines.

The incident occurred last week at a New Jersey Amazon warehouse when a robot punctured a nine-ounce aerosol can of bear repellent. Fifty workers were sickened, 24 workers were hospitalized, and one was intubated and placed in intensive care in critical condition. According to a statement from Amazon, other employees were treated on scene. Many of the complaints involved breathing problems and burning in the throat and eyes.

The bear repellent contained highly concentrated capsaicin, which is a form of pepper spray. Some experts say that bear spray isn't quite as incapacitating as the pepper spray made to be used on humans, but it is very irritating nevertheless. According to the BBC, however, bear spray can cause people to have a temporary but nearly total loss of vision and restrict their breathing severely.

The Retail Wholesale and Department Store union had harsh words for Amazon, who it says repeatedly places its workers' lives at risk. Union President Stuart Appelbaum said: "Amazon's automated robots put humans in life-threatening danger today, the effects of which could be catastrophic and the long-term effects for 80 plus workers are unknown."

He added that the union won't back down until the firm is held accountable for this and many other "dangerous labor practices."