TARRAGONA, Spain (Reuters) - One person was killed, another was missing and six were injured in an explosion and fire at a chemical factory in northeastern Spain, local authorities said.

Slideshow ( 6 images )

Black smoke billowed above the factory in Tarragona, following what rescue services called a “chemical accident”. However, authorities said there was no evidence of any “toxic cloud”.

Two of the injured were in a critical condition, Miquel Buch, from the Catalan regional government, told TV3.

A spokesman for Catalonia’s rescue services said the fire had been contained, adding that several of the injured had suffered burns.

The building in which one person died collapsed near the factory. This was due to a shockwave from the explosion, media including La Vanguardia and El Pais newspapers said.

“We dispatched two medical units (to the collapsed building) which confirmed the death of one person and treated a second person with less severe injuries,” Catalonia’s emergency medical service said in a tweet.

Spanish Prime Minister Pedro Sanchez’s office said he was in touch with Catalan authorities and that Madrid was ready to “provide the necessary support due to this serious event, which has caused several injuries and substantial material damage”.

More than 20 fire trucks, 11 emergency medical service vehicles and a helicopter attended the incident.

The civil defence agency advised people nearby to stay inside with doors and windows shut as a precaution, but added: “There is no evidence of a toxic cloud.”

Local trains between Tarragona and neighbouring Port Aventura were suspended on police orders before later resuming services, the train operator Rodalies said, while the regional transport authority said some roads had been closed.

The affected company is Industrias Quimicas del Oxido de Etileno, the fire brigade said.

According to its website, the company is owned by CL Grupo Industrial SA, a Spain-based group with operations in the consumer goods, energy and industrial sectors. The company could not immediately be reached for comment outside business hours.