At least 22 people, including three labourers, sustained severe burns after a massive explosion triggered a blaze on a naphtha pipeline on the premises of Haldia Petrochemicals Limited (HPL) in East Midnapore during the early hours of Tuesday.

The fire, which broke out around 4.30am in ward 13 at Chiranjeevpur in Haldia, rapidly engulfed several shanties and damaged overhead power supply lines along the Haldia-Panskura railway section, disrupting train services between Haldia and Howrah for the entire day.

Fifteen fire tenders battled the flames for nearly five hours from around 5am before bringing the blaze under control using foam and water. Hundreds of families fled their homes in panic as the fire spread rapidly, later taking shelter in relief camps.

All the injured were initially taken to hospitals in Haldia and Contai before being shifted to Calcutta for advanced treatment. Police said the condition of at least two victims remained critical.

The police and HPL authorities have launched separate investigations into the incident. While the exact cause is yet to be established, preliminary findings point to either a leakage caused by lightning during a thunderstorm or possible illegal tapping of the highly inflammable pipeline.

In an official statement, HPL said: “Preliminary information suggests that the incident may have occurred in the vicinity of an unauthorised naphtha theft point located near the plant. Naphtha is a highly combustible and extremely flammable hydrocarbon, and the company has consistently cautioned local communities against any unauthorised access to or handling of petroleum products due to the serious safety risks involved. The exact cause of the incident is currently under investigation in coordination with the relevant authorities.”

East Midnapore superintendent of police Angshuman Saha said: “The injured were first brought to Haldia Hospital. From there, nine people were shifted to Tamralipta Government Medical College and Hospital. Later, all of them were referred to Calcutta. The cause of the fire is under investigation.”

HPL, located around 125km from Calcutta, is a naphtha-based petrochemical complex. According to petrochemical sources, naphtha was being transported through the pipeline from a vessel anchored at Haldia Port to the refinery when the accident occurred.

Residents claimed they had noticed a strong smell of gas from Monday evening and had alerted security personnel. They alleged that despite being informed, no immediate preventive measures were taken.

Eighteen-year-old Narayan Bhuniya, who suffered burns, along with his 46-year-old mother Mita Bhuniya, recounted the horrifying experience from his hospital bed. “We live in a hut outside the petrochemical plant’s boundary wall. A strong smell of gas had been coming from the area since Monday evening. We informed the security guard, who inspected the area and asked everyone not to smoke or light any fires near the pipeline at night. He said the authorities would take action in the morning. We went to sleep, but were suddenly awakened by a deafening explosion and intense heat. Local people rescued my mother and me and took us to the hospital,” he said.

Residents said a loud explosion shook the area before flames spread rapidly through nearby settlements. Several houses caught fire, triggering panic among residents who rushed out of their homes. Firefighters evacuated those trapped in the affected locality.

Local people also alleged that poor maintenance of the pipeline could have contributed to the accident.

The incident also severely affected railway operations. Train services from Haldia station remained suspended throughout the day after the blaze damaged infrastructure near the railway line. Railway authorities operated the Haldia-Howrah local from Durgachak station, while the Haldia-Asansol Express originated from Tamluk.

Hundreds of displaced residents of shanties have been accommodated in relief camps, where food and other essentials are being provided.

Acting on the instructions of chief minister Suvendu Adhikari, Haldia BJP MLA Pradeep Kumar Bijli supervised the rescue operations from Tuesday morning, coordinated hospitalisation of the injured and oversaw relief arrangements for displaced families.

He said: “If there is an industry, accidents can happen. Instead of blaming anyone, we believe our immediate responsibility is to ensure proper treatment for the injured and provide shelter and food to those who have lost their homes.”