New DelhiThe Delhi Pollution Control Committee (DPCC) is probing the Saturday’s chemical leak in Tughlakabad, which triggered toxic fumes that left 475 schoolchildren sick with breathlessness, eye irritation, nausea and severe headache. According to a Delhi environment department official, DPCC officials have already collected samples from the spill site on Saturday night and they are being tested.“Gas samples from the site has been collected and are being tested by the DPCC. We need to ascertain what the chemical is,” the official said.Delhi environment secretary Keshav Chandra told HT a report is being prepared on the leak. “We have also issued a show cause notice to the Container Corporation Of India Ltd (CONCOR) regarding the incident involving hazardous chemicals,” Chandra said.The liquid chemical, which has been initially identified as chloromethylpyridine, is believed to have leaked from a couple of broken barrels inside an iron container, which was kept in the depot overnight before being transported to Sonepat in Haryana early on Saturday. This chemical, used in fertilisers, insecticides and certain drugs, is a known eye and respiratory irritant.According to fire officials, when sunlight fell on the chemical spilled on the road, it triggered a chemical reaction and produced the toxic fumes. After the leak, the children had irritation and redness in the eye, nausea, vomiting, dizziness and difficulty in breathing. Some children were unconscious when they were brought to the hospital.In December 1984, a similar gas leak at the Union Carbide factory in Bhopal — which also produced pesticide — had left thousands of people dead and many more maimed for life.Delhi chief minister Arvind Kejriwal has also ordered a magisterial probe into Saturday’s incident and fix responsibility for the chemical leak at the depot, adjoining the school.An expert team from AIIMS visited the spot on Sunday.Experts say that this chemical is toxic in nature but not fatal unless consumed in a very high dose. “It is a hygroscopic substance that tends to absorb moisture from the air, liquefies and generates fumes. Unlike gases, fumes have a limited spread, which is why the effect in this case was localised,” an AIIMS doctor had said after Sunday’s visit.