At least six delivery contractors who work at the tech giant’s plant in Bathgate have tested positive in the last week, with around two dozen others now told to work from home.
It is understood that the outbreak centres around a small office on the warehouse site shared by more than 30 contractors.
Two workers who use the office are thought to have tested positive on Monday or Tuesday last week, with four further cases emerging between Friday and Sunday.
The cases were confirmed despite the use of perspex divider panels to separate workstations in the office, and the requirement for staff to wear face masks.
But one person with knowledge of the setting said that, while Amazon UK had been “really good” at implementing social distancing rules across the company, workers had previously been concerned about the size of the room and the continual use of air conditioning.
A spokesperson for Amazon told The Scotsman: “We are supporting the individuals who are now in quarantine.
"Since the early days of this situation, we have worked closely with local authorities to proactively respond, ensuring we continue to serve customers while taking care of our associates and we’re following all guidelines from local officials about the operations of our buildings.
"We have implemented proactive measures at our facilities to protect associates including increased cleaning, maintaining social distance in our sites, and adding distance between drivers and customers when making deliveries.”