The Ocado stock price was down around 2% as of 9.20am local time, after the grocer said a fault in a battery prompted a robot to catch fire at its flagship distribution centre in Andover, Hampshire, in February.
The group is famed for its warehouses run by heavy robots, and holds patents on a range of technology.
It said that “an electrical fault at one of the battery charging units at the edge of the ambient storage grid caused the plastic lid on the top of a grocery-carrying robot to catch alight.”
Ocado confirmed that it had taken several steps to eliminate the risk of such an event ever happening again, including the removal of the plastic lid on its robots.
The fire in February raged for four days and caused enormous damage, with orders disrupted, local homes evacuated and more than 300 firefighters involved in extinguishing the blaze.
At the time Ocado apologised to people affected by the incident and predicted a drop in sales because of its reliance on the warehouse, which could process 65,000 orders a week.