Pesticide in cooking oil more than five times more concentrated than commercial version, according to forensic report
The free school lunches that killed 23 Indian children last week were contaminated with concentrated pesticide that is not widely available, according to the district magistrate overseeing the police investigation.
The children fell ill within minutes of eating a meal of rice and potato curry in their one-room school in Bihar state on Tuesday, vomiting and convulsing with stomach cramps.
The lunch was part of India's mid-day meals scheme, which covers 120 million children and aims to tackle malnutrition and encourage school attendance. It had already drawn widespread complaints over food safety.
The deaths sparked protests in Bihar.
An initial forensic investigation found that the meal had been prepared with cooking oil that contained monocrotophos, an organophosphorus compound used as an agricultural pesticide, Ravindra Kumar, a senior police official, told reporters on Saturday.
The pesticide found in the oil was more than five times more concentrated than that used in a commercial version, according to a forensic report.
"It is highly poisonous, it's highly toxic, and, therefore, it has to be diluted when used as commercial pesticides," said district magistrate Abhijit Sinha.
"Typically it has to be diluted five times. So one litre of monocrotophos is mixed with five litres of water."
Sinha said the concentrated form was not widely available and the pesticide was normally sold commercially in the diluted state.
Police said on Friday they suspected the cooking oil used in the meal was kept in a container previously used to store the pesticide. They are still looking for the headmistress of the school, who fled after the deaths.
The World Health Organisation describes monocrotophos as highly hazardous and that handling and application of it should be entrusted only to competently supervised and well-trained applicators.
The Food and Agriculture Organisation of the United Nations says all waste and contaminated material associated with the chemical should be considered hazardous waste and destroyed in a special high-temperature chemical incinerator facility.