Among its activities, IOCL transports liquefied petroleum gas (LPG) produced in its refineries to cylinder filling facilities through terrestrial pipelines, railway tank trains and road tankers.

Around 10:30 p.m., while crossing the town of Chala, between Kannur and Thalasseri, the driver tried to overtake a vehicle and, in so doing, hit a concrete road divider near the Bhagavati temple bus stop.

The concrete divider started at the temple bus stop –where the slope from the adjacent hill levelled off– and extended 200 metres up to the next junction.

The leaked liquid LPG and its heavy vapors descended there and flowed for 170 metres through an irrigation water canal running north to south and crossing the highway roughly at the spot where the accident occurred.

Most of the persons living around the accident spot evacuated their homes, moved away for some distance and stood on the street along the water canal.

[1][5] Ignition, whose origin is unclear, occurred around 20 minutes after the collision[5] and resulted in a flash fire of the gas spread around the overturned tanker, in the water canal and in the low-lying area on the south.

A huge fireball formed, and half of the burning tank rocketed upwards, flew over the coconut groves and fell about 400 metres away.

[citation needed] Victims, who were those who evacuated their homes but were standing along the highway and the canal, suffered burns from the first flash fire and the BLEVE.

Twenty people died due to burn injuries in various hospitals in a period between 24 hours to 30 days from the time of the incident.

[citation needed] Twenty-two people gave statements in a magisterial inquiry conducted by Kannur District Collector Rathan Kelkar.

However, in the same inquiry a Kerala Public Works Department (PWD) official stated that the divider blocks were painted in black and white reflector stripes and a warning sign was present.

It further recommended that authorities should ensure strict enforcement of the provisions of the Motor Vehicles Act requiring the use of back-up drivers for certain type of journeys and services.

In press conferences after the accident, Chief Minister Chandy stated that improper design of the concrete lane divider was a significant cause of the disaster.

Residences were evacuated in a 500 metre radius, and the highway was closed for 12 hours until a IOCL emergency recovery tanker removed the inventory from the overturned vehicle.