Several firefighters were injured on Wednesday, two seriously, in an explosion at a building in Roswell, New Mexico, where fireworks were being stored for the city’s annual July Fourth celebrations, police and city officials said.

The blast occurred shortly after noon at a building on the grounds of the Roswell International Air Center, a commercial airport on the southern outskirts of the town, said Todd Wildermuth, a spokesman for the city.

He said about a dozen firefighters were in and around the building "doing some preparation work" for the city’s upcoming July Fourth Independence Day fireworks display when the explosion occurred.