HOUSTON - Three people were killed and one person remains missing in a blast at a packaging plant in the US state of Louisiana on Wednesday.

The explosion occurred early Wednesday at the Packaging Corporation of America, located north of Lake Charles, a city in the southwestern part of Louisiana, according to the Times-Picayune, an English daily in the state's city of New Orleans.

Several others were injured in the blast. An air medic helicopter has landed near the plant to help the wounded.

The report did not mention the cause of the explosion. Police have rushed to the site.