Three people were injured when a huge explosion rocked a chemical plant in Port Neches, Texas, U.S., early Wednesday, sending a large fireball into the sky and triggering a mandatory evacuation.

Two TPC employees and one contractor were injured during the blast. They have all been treated and released from their hospitals. At the time of the blast, 30 employees were on-site, and according to TPC,

"At this time, personnel at the site have been evacuated. We have accounted for all site personnel and three personnel have sustained injuries and are being treated," TPC Group, which operates the plant, confirmed in a statement, noting that it had activated its emergency response plan.

The blast occurred at 1:00 a.m. local time and was felt miles away.

Almost every home in the neighborhood felt some kind of impact, local media said.

The plant produced chemical and petrol-based products. It's located about 80 miles east of Houston in the city of Port Neches, Texas.

Warning that the situation was "actively changing", local fire authorities urged residents to pay attention to the news for shelter and evacuation instructions in Port Neches.