Local emergency officials said hundreds of people had been evacuated from the site.
The state-run oil company initially reported that three workers were injured but later raised the number.
Veracruz state Gov. Javier Duarte's Twitter account called the blast at the plant in the city of Coatzacoalcos a "strong explosion."
Mexican striker Javier “Chicharito” Hernández limped off with pain in his left knee and was replaced by Kevin Kampl at minute 69.
Mexico's foreign Minister said that so far there are no reports of Mexicans injured or killed in the Brussels attacks.
An altercation between Klan members and counter-protesters erupted in Anaheim.
They were taken care of in the prison infirmary.
Police and firefighters say hospitals treated at least 35 people from several states, Mexico and Canada. Six people remained hospitalized Wednesday, including two in critical condition.
Authorities initially reported seven injuries, but searchers discovered the burned body of a man later in the day.
The blaze apparently started in an area used to store stolen fuel.