Ammonia leak: Safety audit of Madras Fertilizers Limited exposes chinks in operation

The audit team recommended a study which will be conducted by IIT Madras. The NGT bench has granted IIT Madras three months time to submit the report.
Tamil Nadu Pollution Control Board headquarters in Chennai (TNPCB website)
Tamil Nadu Pollution Control Board headquarters in Chennai (TNPCB website)

CHENNAI: Even as concerns were expressed over the hazardous ammonium nitrate stored in Manali, a safety audit of Madras Fertilizers Limited (MFL) has exposed chinks in its operation and the plant is found to be operating without adequate monitoring systems, including ammonia sensors, in place.

The Tamil Nadu Pollution Control Board (TNPCB) had directed for a safety audit of MFL following an order from the southern bench of National Green Tribunal (NGT), which took suo moto cognizance of the ammonia leak incident in May this year that was reported by The New Indian Express.

The audit team has made critical observations and recommended around 20 measures. "Damaged buildings, damaged roofs with erosion and corrosion of pipe lines and support structures and elevated platforms can result in serious accidents. To ensure safety, suitable isolation should be provided till they are rectified or removed from service," the audit report said.

The report also highlights that there are some parts in the plant operating system which may undergo fast deterioration or fail and get damaged unexpectedly due to slippages in preventive maintenance schedules and due to various process deviations. "It is therefore recommended to have an 'FMEA study' by maintenance experts and also to develop a planned maintenance schedule and control plan for the plant and the identified critical equipment as per the study," it says.

The study will be conducted by IIT Madras. Madhav Kumar, associate professor from Environmental and Water Resources Division, will commence the monitoring work from August.

The NGT bench, comprising Justice K Ramakrishnan and expert member Saibal Dasgupta, has granted IIT Madras three months time to submit the report and posted the matter to November 25, 2020.

After the May ammonia gas leak incident, TNPCB directed MFL to restart the unit only after installation of at least two ammonia sensors at the rear end of the unit in the direction of the village where the  complaint was received, but MFL restarted the unit without any installation. However, it was reported that MFL placed a purchase order. "The delivery was getting delayed due to the COVID-19 pandemic," an MFL official told The New Indian Express and also in the official response to TNPCB that was recorded by the tribunal.

MFL was to install a total of 11 new ammonia sensors on or before June 2020 since the existing 10 ammonia sensors were not functioning since 2016 due to Cyclone Vardha. The plant was also asked to restore the Continuous Ambient Air Quality Monitoring Systems (CAAQMS). Out of 5 CAAQM stations, four are not in operation. Also, the Electromagnetic Flow Meter (EMFM) was not connected to Care Air Centre, TNPCB and Central Pollution Control Board (CPCB).

MFL informed the TNPCB that outputs from EMFMs are available locally but could not be uploaded due to outdated model instruments. Hence latest EMFMs will be procured by December 2020.

MFL was in operation continuously during the COVID-19 lockdown period as per the directions of the Department of Fertilizers to meet the fertilizer demand of farmers since it comes under essential commodities and produces about 1,200 tonnes per day of urea. The incident, MFL claimed, happened during maintenance shutdown of the plant.

The sequence of events presented by MFL says that on May 14 at 7.30 pm, a Cooling Water Pump bearing failure was noticed and the urea plant was shut down as per normal safe shutdown procedure. "During safe shutdown, we found mild passing in Pressure Safety Valve (PSV) in idle Ammonia Reflux pump discharge and it was isolated. The ammonia vapour was let out to the atmosphere through a closed circuit with proper dilution. This is the usual practice being followed by all the fertilizers companies in India, as per national and international standards in case of line passing," officials said.

Ammonia smell complaint was received over the phone at 8.30 pm from the nearby Mathur resident area. Immediately MFL officials visited the spot and observed no ammonia smell and the message was conveyed to TNPCB officials," MFL officials claimed. However, Mathur residents complained that the leak was severe and caused eye irritation, nausea and breathlessness. Locals had complained about similar leaks from MFL several times in the past.

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