The Chala LPG tanker disaster was a road transport accident that occurred on August 27, 2012, on Indian National Highway 17 (now NH 66) at Chala in the Kannur District of India's Kerala State. Some consider it the worst hazardous material road transport accident in India in terms of casualties. The accident occurred when an Indian Oil Corporation Limited (IOCL) LPG road tank truck hit a road lane divider, overturned and exploded, starting several building fires between 9:30 p.m. and 11 p.m. The accident caused the deaths of 20 people and injured another 15.
Background
Indian Oil Corporation Limited (IOCL), owned by Government of India, is a diversified, integrated energy major with presence in all the streams of oil, gas and petrochemicals.
IOCL transports liquefied petroleum gas (LPG) produced in its refineries to cylinder filling facilities through terrestrial pipelines, railway tank trains and road tank trucks. The Indian Oil Corporation (IOC) owned cylinder bottling plant in Chelari in Kozhikode district in Kerala receives LPG through road tank trucks from Mangalore LPG Import Facility (MLIF) owned by IOCL situated 264 km away in Karnataka state.
LPG tankers with drivers are supplied to IOCL by contractors. The safety of transportation and emergency services is managed by IOCL. Bullet shaped tanks mounted on trailer trucks normally have 17-ton LPG capacity in three compartments. Petroleum Rules 1976 require petroleum transportation vehicles to have a license from the Petroleum and Explosives Safety Organization (PESO).
National Highways in India are constructed and maintained by the National Highway Authority of India (NHIA) and State Public Works Department.{ "type": "FeatureCollection", "features": [ { "type": "Feature", "properties": { }, "geometry": { "type": "Point", "coordinates": [ 75.42829227432777, 11.848513419700142 ] } } ] }
Accident
On August 12, 2012, between 9:30 p.m. and 10:00 p.m. an LPG truck coming from Mangalore to the Chelari filling station of IOCL in Kozhikode district hit a concrete road divider and overturned near Chala temple bus stop between Kannur and Thalasseri towns.
The lane division was installed to segregate traffic in opposite directions. The concrete divider started at Chala temple bus stop - where the descend from hill levelled off - and extended 200 meters up to the next junction. The divider was constructed by fixing 50 cm high concrete blocks along the center line. The dividers, originally painted white and black strips, were blackened with vehicle exhausts. The concrete lane divider in Chala did not have a warning sign installed on it to indicate start of division or presence of obstruction in the middle of the road. In Kannur August night temperature is normally between 25oC to 28oC and humidity is above 80%. Mild rain was present during the time of accident. There were a few one and two storied commercial buildings on the north side of the highway and several houses on both sides. The nearest house was within 20m of the highway.
After the truck overturned the tank drain valve of one of the tank compartments broke and started leaking liquid LPG. The land on the south side is 2-3 meter and on the east side is 1 meter below the highway. The leaked liquid LPG and heavy gas flowed for 170 meters through an irrigation water canal parallel to the street on the south side of highway. This street connected the houses in coconut palm groves on the south side with the highway.
The driver was able to exit the cabin and alert nearby residences before ignition. 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.
Explosions and fire
First ignition occurred between 10 and 20 minutes after overturning of the truck. This was a flash fire explosion in the gas spread around the overturned truck, in the water canal and in the low-lying area on the south side. The gas settled in the canal is said to have burnt for 1 to 2 minutes. Persons who had evacuated their houses but stood on the streets on the south and north side of the highway suffered burn injuries from the flash fire explosion that they hadn't expected. After the first explosion the fire subsided to a jet fire at the leaking portion of the overturned bullet tank. During this period the neighborhood had attempted search and rescue in fire impacted houses.