Cement and RMC are industrial activities that are equally vulnerable to any lapses that may occur in any other industrial activity. The cover story focuses on some of the past workplace incidents that are significant.
Workplace safety is of paramount importance. Just a month ago, the news of a blast at NTPC Limited’s Unchahar power plant in Raebareli, Uttar Pradesh, claimed lives of 43 employees. It is a well-accepted fact that we take safety very lightly and are not doing enough collectively. Incidentally, this plant supplies fly ash to several cement units. ICR decides to take a deep dive into the past few incidents on workplace safety.
The NTPC Limited’s Unchahar power plant blast claimed lives of 43 persons and 85 were treated at hospitals in Raebareli, Lucknow and New Delhi. The blast took place in the boiler of Unit no 6 (500MW) on November 1, 2017. The blast occurred in the boiler area of the recently commissioned 500 MW unit. The equipment for the plant was supplied by Bharat Heavy Electricals Ltd. “There was clinker formation that choked the bottom ash outlet,” as informed by NTPC executive. Blockages in the flue gas pipe in a unit led to the blast. Hot fuel gases and steam let out by the blast severely injured several workers and other employees While boiler cleaning operations in thermal plants are automated, there are instances when it needs manual cleaning in the case of clinker formation. Clinkers are lumps formed after burning of coal at high temperature in the furnace. With the clinkers choking the bottom ash outlet, the pressure in the boiler went up thereby melting the water valves surrounding the boiler. This created a vent, with hot flue gases and steam at high temperature escaping. This got mixed with ash (around 200°C) present and injured and killed the personnel present. It is a very uncommon incident. The economizer duct blew releasing flue gas and steam. There was a pressure build-up. Due to the impact, people who were working there were thrown back a distance of 10-20 m.
NTPC as an organisation has very good safety records and we have not heard of any major accidents in over the last 20 years. It is very difficult to draw any specific conclusions since the matter is still under investigation. The severity of disaster clearly indicates that the incident will throw a lot much learning to the fraternity.
Korba Chimney Collapse, 2009
The chimney collapse occurred in the town of Korba in the State of Chhattisgarh on September 23, 2009. It was under construction for the Bharat Aluminium Co Ltd (BALCO). Construction had reached 240 m (790 ft) when the chimney collapsed on top of more than 100 workers who had been taking shelter from a thunder storm.
Plans specify a 275-m chimney for the construction of a thermal power plant by BALCO, which is owned by Vedanta Resources. The incident happened during extreme weather conditions involving lightning and torrential rainfall. Workers sought shelter from the rain in a nearby store room, and a lightning strike at approximately 4 PM brought the chimney down on top of them. A rescue attempt was initiated following the collapse. Ongoing rain obstructed effort to retrieve the trapped workers. At least seven of the wounded were hospitalised. BALCO initially did not discuss the incident at length, strange only that “there is an accident and some people are injured”; claiming to be too busy with the rescue effort to make a longer statement. The state government believes that BALCO had been overlooking security aspects. In November 2009, the project manager from GDC Ltd was arrested, as well as three officials from Vedanta Resources which manages BALCO.
Key learnings: The National Institute of Technology (NIT), Raipur observed that the materials used were of substandard quality and technically faulty in design. NIT also concluded that there was improper water curing and that soil at the site was not up to code. Additionally, supervision and monitoring was found to be negligent. There was no preparedness to face thunderstorm or any kind of extreme weather conditions.
Jaipur Oil Depot Fire, 2009
The fire broke out on October 29, 2009 at 7:30 PM at the Indian Oil Corporation (IOC) oil depot’s giant tank holding 8,000 kilolitres (2.80,000 cu) of oil, in Sitapura Industrial Area on the outskirts of Jaipur, Rajasthan, killing 12 people and injuring over 200. The blaze continued to rage out of control for over a week after it started and during the period half a million people were evacuated from the area. The oil depot is about 16 km south of the city of Jaipur.
The incident occurred when petrol was being transferred from IOC’s oil depot to a pipeline. There were at least 40 IOC employees at the terminal, situated close to the Jaipur International Airport when it caught fire with an explosion. The MET department recorded a tremor measuring 2.3 on the Richter scale around the time of the first explosion at 7:36 PM, which resulted in shattering of glass windows nearly 3 km from the accident site.
The fire was a major disaster in terms of deaths, injury, loss of business, property and man-days, displacement of people, environmental impact in Jaipur. As per eyewitnesses, having factories and hotels around IOC’s Sitapura (Jaipur) Oil Terminal they felt presence of petrol vapour in the atmosphere around 4:00 PM on October 29, 2009. Within the next few hours the concentration of petrol vapours intensified making it difficult to breathe. The Ayush Hotel in the vicinity of the terminal asked all its guests to vacate the Hotel to avert any tragedy. Adjacent to the Terminal wall was the workshop of Morani Motors (P) Limited whereas per eyewitnesses the cars parked on the roof top were thrown up in Air to about 10 feet and 35 new Hyundai brand cars were completely damaged. The police, civil administration and fire emergency services were oblivious of the situation developing in Indian Oil terminal.
The staff in the terminal had contained the leak and flow of petrol panicked and reported the matter to nearby Sanganer Sadar Police Station. Within the next 30 minutes the local police chief and District Collector were on the spot along with Indian Oil general manager, but with no plan to deal with the situation. The nearby industries, which were running second shift, were cautioned to vacate the area. At 7:35 PM, a huge ball of fire with loud explosion broke out engulfing the leaking petrol tank and other nearby petrol tanks with continuous fire with flames rising 30–35 m (98–115) and visible from a 30 km radius. The traffic on adjacent National Highway No. 12 was stopped leading to a 20 km long traffic jam.
The Jaipur International Airport is just 5 km away from the accident site. Both the Army and experts from Mumbai were employed on October 30, 2009 to contain the fire, which started when an oil tanker caught fire at the depot in the Sitapura Industrial Area. The district administration disconnected electricity and evacuated nearby areas to limit the damage. The fire still raged on October 31, 2009, in the IOC depot, at Jaipur, after a defective pipeline leak that set fire to 50,000 kilolitres (1,800,000 cu) of diesel and petrol out of the storage tanks at the IOC depot. By then, the accident had already claimed 11 lives and seriously injured more than 150.
Key learnings: The District Administration and IOC had no disaster management plan to deal with this kind of calamity. The local fire officers were ill equipped to deal with fire accidents of this magnitude. They remained onlookers and no efforts were made to breach the terminal wall to get closer to kerosene and diesel tanks to cool them with water jets.
Industrial accidents are caused by chemical, mechanical, civil, electrical, or other process failures due to mishap, negligence or incompetence, in an industrial plant which may spill over to the areas outside the plant causing damage to life and property. Major threats encountered in industrial accidents are fire, explosion, toxic release, poisoning and or combination of any of these. It is important to check the probable causes of accidents which are process deviations i.e pressure, temperature and flow, parameters with regard to the state of the substance, i.e., solid, liquid or gas, proximity to other toxic substances.
Probable causes: Boiling liquid expanding vapour explosion (BLEVE) on the chemicals during transportation, electrical failure, cutting and welding, open flame, carelessness, poor housekeeping, smoking, sabotage, etc.
Effects of accidents
Meteorology of the area, wind speed and direction, rate of precipitation, toxicity/quantity of chemical released, population in the reach of release, probability of formation of lethal mixtures and other industrial activities in vicinity.
We have narrated three industrial disasters only to provoke the thought process of our readers. Cement industry and RMC business are no exception to any of the incidents narrated above. An industrial disaster of this kind leaves a stigma behind and we as professionals have to take learnings from it so as to avoid similar occurrences in future.