At least five people have been injured in an explosion at a chemical plant in Gaotang county in East China's Shandong province on Monday, Xinhua News Agency reported.

Internet users said the explosion rocked neighboring residential and commercial buildings.

Cracks appeared in the glass walls of a large store 1.5 km from the factory. The county capital, 3 km from the explosion, also felt the blast.

The explosion happened at 6:45 am in a workshop producing Choline chloride, an additive used in feed to accelerate growth.

A publicity official with the local government told iqilu, a Shandong-based online news portal, that no deaths have been reported, and there was no leak of toxic chemicals.

The injured were sent to hospital, and an investigation has been launched into the cause of the explosion.