Multiple Amazon Workers Hospitalized, Warehouse Evacuated after Exposure to 'Unknown Substance'

Several Amazon employees were hospitalized after being exposed to an "unknown substance" at a distribution center in California, authorities said.

The Cal Fire/Riverside County Fire Department said firefighters responded to the Amazon Fulfillment Center in Eastvale, California shortly after the incident was first reported to authorities at 4:38 p.m. on Saturday.

Firefighters evacuated 150 employees from the warehouse, at 4950 Goodman Road, the department said on Twitter.

Six employees were transported to area hospitals for treatment. The employees had sustained injuries that were described as minor to moderate, according to the tweet.

"They were exposed to an unknown substance inside the building," said Jody Hagemann, a spokeswoman for Cal Fire/Riverside County Fire Department, told The Press-Enterprise.

The fire department said hazmat teams arrived at the warehouse to isolate the substance involved and identity it.

But in a tweet on Saturday evening, the department said the team was unable to locate anything inside the facility.

"HAZ MAT team made entry into the building and were unable to locate anything. Incident will be terminated shortly," the tweet said. "The business will reopen and resume normal operations."

Amazon spokesperson Lisa Levandowski told Newsweek: "We evacuated our building yesterday out of an abundance of caution. The safety of our employees and delivery partners is our top priority. We appreciate all the efforts of our local first responders yesterday."

The incident comes weeks after Amazon was fined for coronavirus safety violations at two warehouses, including the one in Eastvale.

California's Division of Occupational Safety and Health investigated the Eastvale fulfilment center and the Amazon delivery center in Hawthorne after employees complained about their working conditions amid the pandemic, The Los Angeles Times reported.

The employees alleged that Amazon did not adequately promote social distancing and did not stop operations to clean and disinfect parts of the warehouses where infected workers had spent their shifts.

Investigators found the facilities failed to mitigate the exposure of employees to the coronavirus by not providing effective safety training and fined the company around $1,500.

"The employer did not ensure that all employees had access to, viewed and understood all COVID-19 training materials, and employees were unaware of key elements in the training materials, including but not limited to, sanitation of work stations and frequently touched objects in the workplace," the citations, dated October 6, said.

Early last month, Amazon revealed that almost 20,000 Amazon and Whole Foods Market front-line employees across the U.S. had tested positive or been presumed positive for the virus as of late September.

This week, the company announced plans to hand out bonuses worth more than $500 million to U.S. workers over the holiday season.

This article has been updated with a statement from an Amazon spokesperson.