Toxic orange cloud spreads across two towns in Spain (VIDEO)

BARCELONA (AP) — Spanish authorities have ordered the residents of two northeastern towns to stay indoors after a chemical explosion at a warehouse spread a large, orange toxic cloud over the area.

A spokeswoman for Catalonia's regional firefighting department said the blast occurred Thursday when products being delivered to a warehouse in the city of Igualada became mixed, exploded and set a truck on fire. She said two people were slightly injured.

The Red Cross cited firefighters as saying the chemicals were nitric acid and ferric chloride.

The spokeswoman said firefighters are urging some 40,000 residents of Igualada and the nearby town of Odena to stay indoors until the cloud dissipates. She said the town's water systems are also being checked.

The official spoke on condition of anonymity in keeping with department regulations.