(KAMR/NBC News) Four children are dead after a pesticide created poisonous gas inside their Amarillo, Texas home.

Officials say someone tried to wash a pesticide out from underneath the home with water.

"There was a fumigant that they were using to get rid of pests here. This fumigant contained a chemical called aluminum phosphide, and when mixed with water it creates a gas called phosphine gas which is highly poisonous," said Amarillo Fire Captain Larry Davis.

When crews arrived one child was already unconscious and couldn't be revived. Three more children died at a hospital.

The conditions of the other six people at the home have not been released.

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