As a boiler exploded at Amudan Chemicals located in Phase 2 of Dombivli MIDC area around 1.40 pm, the impact of the explosion and the resultant blaze affected adjacent factories and houses, they said.
The affected chemical factory produced food colours and used peroxides that are highly reactive and unstable chemicals that can cause violent explosions under certain conditions, the National Disaster Response Force (NDRF) said
The blast was so loud that it was heard a kilometre away, an eyewitness said.
Glass windows of adjoining buildings cracked while many houses in the vicinity were damaged, officials said.
Thick clouds of smoke could be seen hovering over the factory.
Eight men and three women were killed but their bodies were charred beyond recognition, said Yasin Tadvi, chief of the disaster management cell of the Thane Municipal Corporation.
As per the preliminary information, those killed were working in neighbouring factories, Maharashtra Industries Minister Uday Samant said.
The state Industries and Labour Department issued a statement saying the boiler in the factory was not registered under the India Boiler Regulations, 1950.
Terming the incident as horrible, Chief Minister Eknath Shinde said some more people are feared trapped in the factories around the chemical factory.
"Our priority is to rescue those people. Eight persons have lost their lives and more than 60 were injured," he said from the factory site.
The government has taken a serious note of the incident and has decided to categorise the industries as A, B and C in terms of the hazards they pose
"All most hazardous industrial units falling under the red category will be immediately shut across the state. Such units will be given an option to shift to another location or change the usage (category) like engineering and IT....There will be no compromise on the lives of people," Shinde said
The departments concerned will meet to formulate the process of shifting the units, he said.
The CM announced that the kin of those killed in the blast would be given Rs 5 lakh each and the expenses of those injured would be borne by the government.
The state industries department said the reasons behind the blast would be revealed only after a detailed inquiry.
Deputy Chief Minister Devendra Fadnavis said on X, "My deepest condolences to the families who lost their loved ones."
"Injured are being treated at AIMS, Neptune and Global hospitals, and every kind of assistance is being provided. Praying for their speedy recovery. Various teams and administrative officials are on the spot for rescue operations," he added.
Besides fire brigade, police and local officials, the NDRF, too, was taking part in the rescue operation, officials said.
Minister Samant told PTI that the plant where the explosion took place was not in operation for the last few months and had restarted only a few days ago.
Samant, local MP Shrikant Shinde and MLA Raju Patil visited the site inside the Maharashtra Industrial Development Corporation (MIDC) area, some 40 km from Mumbai
CM Shinde said, "Those found guilty will face action and no one will be spared. I have instructed the authorities to register a case of culpable homicide not amounting to murder."
He later visited the hospital in Dombivli and enquired about the health of the injured.
The impact of the explosion was such that an eatery named Ganesh Bhuvan in the vicinity suffered major damage as it was mostly reduced to rubble.
