From correspondents in Washington, United States, 06:31 AM IST

At least 21 people were injured and two others missing after the roof of a food plant collapsed in the US state of North Carolina, media reports said Tuesday.

According to TV reports, the roof of a food plant that belongs to ConAgra Foods Company partially collapsed Tuesday morning following an explosion inside the plant.

The cause of the blast was not immediately known.

The employees who were at the plant at time of the incident suffered chemical burns and exposed to toxic fumes from ammonia leaks, Mayor Ronnie Williams said. 'There was no warning, no sign. It all happened very abruptly,' he said.

The authorities were searching for the missing people.

(Staff Writer, © IANS)