A massive explosion at the Gaomi Youdao Chemical Co. plant in Weifang, eastern China, killed at least five people, left six missing, and injured 19 others on Tuesday.

Videos show thick smoke rising from the site, and the blast shattered windows at a warehouse over two miles away.

A nearby student reported hearing the explosion, seeing reddish dirt-yellow smoke, and noticing a strange smell.

Over 230 first responders were dispatched.

The plant, which produces pesticides and medical chemicals, had previously been cited for safety risks but was praised for resolving them, Fox News has reported.

The cause of the blast is still unknown.

Written by B.C. Begley