A Hampshire industrial estate and nearby homes have been evacuated after a major fire at an Ocado warehouse that took more than 24 hours to bring under control.The online supermarket had been forced to cancel orders and warned of a “hit to sales” after the huge blaze ripped through its robotic warehouse. Around 200 firefighters were deployed to tackle the blaze which began at the Andover facility at 2.44am on Tuesday.Hampshire Fire and Rescue Service (HFRS) said four of its firefighters had been treated for slight smoke inhalation as they battled to bring the inferno under control.On Wednesday night HFRS announced that the Walworth industrial estate was being evacuated due to the risk of toxins being released or a large cylinder exploding.The fire service said properties will be evacuated within a 500-metre exclusion zone and a 1.6km stretch based on wind direction. Live from #OcadoFire in #Andover which is under control. Members of the public are still asked to avoid the area in Walworth Business Park. If you live nearby please keep windows and doors shut. pic.twitter.com/YVYSsEV0lK— Hampshire Fire and Rescue Service (@Hants_fire) February 6, 2019 The fire has since been brought under control, and in a statement, the HFRS said: “The Ocado warehouse blaze in Andover was declared a major incident by Hampshire Fire and Rescue Service.” It looks like the fire at the #ocado warehouse in #Andover has taken hold again, this time to the right hand side of the building.There is a lot more fire engines on scene than there was this morning with thick black smoke billowing out.More on @BBCSouthNews pic.twitter.com/KKSgGWfzho— Matt Graveling (@mattgraveling) February 6, 2019 On Twitter the fire service played down the smoke rising from the warehouse, and tweeted assurances that it was under control. “This is obviously a terrible event and thankfully no one has been hurt although some firefighters have been treated for smoke inhalation.”A fire service spokeswoman said around 20 families had sought refuge in the rest centre on Wednesday night.She added that it was a “strong possibility” that those working within the exclusion zone would not have access on Thursday morning.Locals had earlier been urged to keep their windows and doors shut due to the smoke from the blaze, while the public was also asked to avoid the area.Ocado said it had been forced to cancel some customer orders because of the fire and that it was “working hard to resume normal service as soon as possible”.While deliveries in the north appeared to be unaffected, customers in parts of the south seemed likely to be hit by the cancellations. The group’s shares dropped 6% as it said it would see a fall in sales growth until it can shift operations to other warehouses following the fire, which took more than 24 hours to contain.On Wednesday morning, the fire service reported that the blaze was under control, but just before 3pm firefighters were filmed hosing down the building once again as thick, black smoke was seen billowing into the Hampshire sky. But it did repeat the warning to residents urging for windows and doors to be kept shut. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. A rest centre has been set up at Harrow Way Community School.Conservative MP for North West Hampshire Kit Malthouse said a number of homes were being evacuated overnight and that alternative accommodation had been provided.He posted on Facebook on Wednesday: “The fire has come and gone during the day, flaring up at times, and I understand it has recently receded, however I would urge people nearby to check online for advice. Firefighters at the scene of Ocado robotic warehouse in Andover, HampshireCredit:PA It’s going to be a loooong night.. 🔥 #AndoverFire #Ocado #MajorIncident #WalworthIndustrialEstate @Hants_fire @hfrs_control @DWFireControl @DWFireRescue pic.twitter.com/nEjOU2PqIf— Lottie (@lottielouises) February 6, 2019 The online grocer said in a stock market update: “Unfortunately the fire which started yesterday morning in a corner of the ambient grid was not contained as we believed, and last night expanded.”Whilst we are informed by the fire brigade that it is now under control, during the night part of the roof collapsed and there has been substantial damage to the majority of the building and its contents.”Once we have had time to assess the damage and prepare a plan to return the customer fulfilment centre to operation, we will update further as appropriate.”As Andover was providing approximately 10% of our current capacity, as a result of this incident there will be a constraint on our ability to meet our growing customer demand and there will be a reduction in sales growth until we can increase capacity elsewhere.”Pictures from the scene taken in the early hours show the sky glowing orange due to the flames and smoke billowing from the building.