KTRK reports that the initial blast happened around 1 a.m. at the TPC Group plant off Highway 366. The facility is approximately 95 miles east of Houston.
Two employees and one contractor were injured in the blast, but all were treated and released from hospitals, officials said.
Numerous videos shared on social media showing a large blaze illuminating the night sky.
This footage, taken on a home security camera of Port Neches native Eddie Ramirez, around a mile away from the blast, illustrates the strength of the explosion, as a loud blast is clearly heard.
In a post to Facebook, the Nederland Volunteer Fire Department said there was a "mandatory evacuation for everyone within a 1/2 mile of the TPC plant" in Port Neches.