Incident 126: Three Robots Collided, Sparking Fire in a Grocer's Warehouse in UK

Description: A collision involving three robots at an Ocado's warehouse in Erith, UK, resulting in a fire but no reports of injuries.
Alleged: Ocado developed and deployed an AI system, which harmed Ocado.

Suggested citation format

Perkins, Kate. (2021-07-16) Incident Number 126. in McGregor, S. (ed.) Artificial Intelligence Incident Database. Responsible AI Collaborative.

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Sean McGregor, Khoa Lam


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Ocado has apologised to customers for cancelling their orders after a major warehouse fire broke out when three robots collided.

Around 100 firefighters and 15 fire engines tackled the blaze at the three-storey depot in Erith, south London, on Friday afternoon.

Hundreds of staff were evacuated but there were no reports of injuries.

The London Fire Brigade said the blaze was “very deep-seated” but that it was under control by 2.17am on Saturday.

Station Commander Steve Vydelingum said that “Firefighters worked hard in hot and arduous conditions inside the warehouse” and that they would “continue to be at the scene into Saturday damping down hot spots”.

Ocado told The Independent that only a small section of the warehouse robot grid had been damaged, and that the facility would return to normal “within the coming week”.

“The incident appears to have been caused by the collision of three bots on the grid resulting in a fire,” the company said in a statement.

“The correct protocols were successfully implemented including the evacuation of the building, the activation of the sprinkler system and the presence of the London Fire Brigade. No one has been injured and all colleagues on site are safe. The damage is limited to a small section of less than 1 per cent of the grid, having been contained by planned fire-attenuation measures.

“Aside from some residual smoke smell, the vast majority of the CFC [customer fulfilment centre] is in good condition. While we expect some disruption to operations, we are working to restore normal service as soon as possible.

“We would like to thank the London Fire Brigade and all the other emergency services for their hard work and professionalism in dealing with this incident.”

Ocado also apologised to customers after it was forced to cancel some deliveries and temporarily block new orders.

Several people complained on Twitter that their orders had been cancelled despite their living as far away as Winchester and East Berkshire. Others said they were relying on deliveries because they were self-isolating with Covid.

“We’re really sorry,” Ocado tweeted. “Due to a major incident at our Erith warehouse, some of our orders have been cancelled. Please be patient with us while we manage this. If this impacts your order, we will be in touch. Thank you.”

Two years ago Ocado lost an estimated £110m when a fire destroyed its warehouse in Andover, Hampshire. A small fire also broke out in a skip at the Erith depot a few months later in August 2019.

Major fire breaks out at Ocado warehouse after three robots collide

Ocado had to cancel orders and shut down the facility for a few days.

Robots may be the future of order fulfillment (and cleaning and gardening), but there's still a long way to go before it's completely safe to rely on them. Online grocer Ocado just found that out after its fulfillment robots caused a fire to break out.

As Engadget reports, Ocado operates a customer fulfillment center (CFC) in Erith, south-east London that's home to over 3,000 robots passing within 5mm of each other as they move around on a grid filling bags with grocery items for orders. However, on Friday last week disaster struck as three robots in the CFC collided causing a fire to break out.

According to Ocado, "The correct protocols were successfully implemented including the evacuation of the building, the activation of the sprinkler system and the presence of the London Fire Brigade. No one has been injured and all colleagues on site are safe. The damage is limited to a small section of less than 1% of the grid having been contained by planned fire attenuation measures."

YouTuber Tom Scott recently posted a video showing how Ocado's robot fulfillment system works:

Although the fire was quickly contained, the CFC remains offline and it could be several days before orders start being filled again. There is a lingering smell of smoke within the facility, which suggests some deep cleaning and air filtration needs to happen before the robots start moving. Having the sprinkler system activate also means Ocado needs to allow all its equipment to dry, which will be helped considerably by the high temperatures in the UK this week.

The positives to take away from this incident include the fact no humans were injured because the facility is all robots. It also proved Ocado's protocols work well. However, the fact the robots collided at all shows there's a software problem to work out, or perhaps it's a sensor problem? Maybe that's a positive, too, as it highlighted something that needs fixing without causing extensive damage.

Back in 2019, Ocado suffered a major fire at its facility in Andover, Hampshire after a detection system failed. It required a complete rebuild, which Ocado only completed it in February this year. So the company will be reassured that its protocols worked this time.

Robots Collide, Causing Fire at Online-Only Grocer in UK

Robots are credited with boosting efficiency in some industrial use cases. But, as a major UK grocery service just found out, that doesn't mean they're not accident-prone like humans. Ocado — which competes with Amazon Fresh — has been forced to cancel orders for some customers after a robot collision sparked a fire at its warehouse in south-east London. The incident appeared to involve three bots on the grid and led to the evacuation of its Erith customer fulfilment center, the company said.

Ocado revealed that the fire triggered the site's sprinkler system, but was contained by its mitigation measures. Nonetheless, the London Fire Brigade was called to the scene to deal with the blaze, the company added. In all, Ocado said the damage was limited to just 1 percent of its grid, adding that it would take a week for the facility to resume operations.

The UK company's south-east London warehouse contains 3,000 robots that move at 13 feet per second when fetching grocery orders. Ocado also licenses its automation platform to others including Kroger in the US, which recently deployed the system at its 375,000-square-foot customer fulfillment center in Monroe, Ohio.

Based on the proximity of the droids and the speedy nature of their task, it's a miracle more clashes haven't occurred. As detailed in a recent CNN report, the bots — described as "washing machines on wheels" — move within five millimeters of each other on a grid-like system to collect items. Ocado even told the news publication "we basically play chicken with them: they go on a collision course only to divert at the last moment."

A robot collision sparked a fire at the UK's top online grocer

Online-only grocer Ocado was forced to cancel some customers’ orders last week following a fire at its London warehouse. This marks the second fire Ocado has experienced at one of its warehouses; this time, a three-robot collision is to blame.

The company announced via Twitter Friday that it would be canceling some orders due to a “major incident.” Soon after, the company released a statement disclosing that a fire had erupted at its Erith Customer Fulfillment Centre following the collision of three robots on Ocado’s automated grid. Thankfully, no employees were hurt.

East of London, Ocado’s Erith CFC houses the company’s largest robotic grocery fulfillment grid. A 2018 feature from The Verge describes the AI-powered grid as a “huge chessboard, populated entirely by robots” each about the size of a washing machine. The robots perform basic tasks like lifting, sorting, and moving groceries and bringing them to human “pickers,” who stand on the sidelines and pack individual customers’ orders. Despite (or perhaps because of) the robots’ simplicity, they’re able to fulfill approximately anywhere from 65,000 to 150,000 orders each week. They’re even able to self-diagnose when they experience a bug and take themselves to “the pits” for a fix if the issue is severe enough.

Ocado’s technology, however, requires its robots to run on extremely thin margins—literally. Due to the construction of the grid, robots may pass within 0.2 inches (5 millimeters) of each other as they buzz by to fulfill their respective orders. This is where last week’s fire appears to have found its origin; when three of the robots crashed, they burst into flames, resulting in an evacuation of over 800 employees and a fall in the company’s share price by about 3 percent.

“The damage was limited to a small section of less than 1 percent of the grid having been successfully contained by our fire attenuation measures, many of which were implemented following our thorough fire safety review in 2019,” Ocado said in a statement. “While the incident has caused some short-term disruption to operations, the vast majority of customer orders are being fulfilled in other parts of the Ocado network.” The company promised via Twitter to contact customers whose orders would be impacted as soon as possible.

Ocado implemented those thorough safety measures in 2019 after its Andover warehouse burned down that same year. The company has since revealed the fire was started by an electrical failure in which the building’s sprinkler system was disabled.

Robot Collision Sets London Warehouse Ablaze, Delays Orders

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