It was the banned agriculture insecticide monocrotophos in the mid-day meal which killed 23 children of the primary school in Chhapra on July 16, declared the Forensic Science Laboratory (FSL) of the Bihar Police on Saturday.
The use of the organophosphorus compound has been banned and restricted globally, but it is widely available in Indian markets as Hilcron, Novicron and Dicron.
Its slightest contamination causes cardio-toxicity, cancer, reproductive problems and birth defects. It was also found to be a major cause for the death of birds globally. Unfortunately, India is the biggest producer and consumer of this poison. It is mainly used here in maize and sugarcane crops.
The FSL pinpointed the substance after testing the samples of the suspected poisonous cooking medium (oil) found in a white plastic container at the mid-day meal (MDM) kitchen site, besides samples of food material from cooking utensils and leftovers.
The FSL scientists also examined the froth from the mouth of the sick.
Additional director general (Headquarters) Ravinder Kumar said, "The forensic scientists used standard analytical method on gas chromatography mass spectrometry (GCMS) machine to find the presence of 'monocrotophos' in the samples of oil, food remains and mixture of rice with vegetables kept in the aluminum cooking utensil. It is used as a pesticide and is very toxic to human beings and animals."
The FSL results were interpreted by using the National Institute of Standards and Technology (NIST) library, which is an internationally accepted database.
The scientists also compared the results with an insecticide standard Hilcron procured from the market and found that the peak retention times matched with the deadly samples collected from the school.
The FSL report also observes that the peak area of the poisonous substance in the oil was more than five times in comparison to the commercially available insecticide.
Kumar refused to comment on how the lethal substance got mixed in the food and said, "The matter is under investigation and our main thrust is right now on collection of evidence. We will definitely take action after that. The absconding principal of the school has nowhere to go."
An FSL source said, "Monocrotophos is an extremely lethal substance and only 20mg per kilogramme of body weight is enough to kill a person. In this particular case, the victims were tender children and even small quantity would have caused death."
The forensic examination of the poisonous samples was done under the guidance of IG (special branch) Dr Paresh Saxena.
Points to ponder
* The extremely lethal substance was found in the cooking oil and food samples tested by FSL scientists
* Though banned and restricted globally, it is easily available in Indian market under various brand names
* Police investigating how it got mixed with the cooking medium and collecting further evidence
* Even 20mg/ kg of body weight is enough to kill a human being. In tender kids, lesser quantity would also be deadly