The death of a toddler and the critical condition of her brother have now been attributed to suspected chemical poisoning.

The parents of Habiba Hisham, 2, and Abdul Rahman Hisham, 6, admitted their children to hospital early Sunday morning after the kids exhibited symptoms of poisoning, including continuous vomiting all day on Saturday. Habiba died from cardiac arrest just six hours later.

Initially, doctors believed food poisoning to be the cause, but now they suspect it may be a banned pesticide.

"We reviewed the family's activities over the last two days again, and the father informed us that he noticed a strange smell coming from the neighbouring apartment," said Dr Khalid Khalfan Sabt, technical director at Al Qassimi Hospital.

The hospital then informed the police and the Sharjah Municipality, which sent a team of investigators who knocked down the door of the apartment to find capsules of aluminium phosphide. The tenants were not in the apartment and had travelled to India. It was unclear how long they had been gone.

Hisham Abdul Rahman Abdul Fattah, the children's father, said yesterday that he had suspected this to be the case as he had noticed the apartment door across the hall from him was sealed with tape.

The death rate from aluminium phosphide poisoning is between 60 and 80 per cent of all cases, and no antidote exists, Dr Sabt said. The product is banned for household and personal use in the UAE, however many suppliers continue to sell the pest control product illegally. The gas is normally used for stored products such as rice, wheat and barley, however its misuse has resulted in many poisoning cases and even death.

Meanwhile, Abdul Rahman's condition has improved slightly, Dr Sabt said.

The efficiency of his heart rate function increased from 25 per cent yesterday to 40 per cent today. However Dr Sabt said the child is still in a critical stage and remains in the hospital's paediatric intensive care unit. Dr Sabt said the method of treatment will not change significantly.

"We are giving him optimal medical support to fight the toxins," he said.

The investigation by the Sharjah Municipality and the police is ongoing.

mismail@thenational.ae