An explosion at the Orient Shopping Center's aquarium on Dec 18 that injured 16 people was caused by a sudden drop in temperature, the Shanghai Administration of Work Safety said on Wednesday.

The blast at the aquarium in downtown Shanghai's East Nanjing Pedestrian Road left one person with a fractured leg.

The upper part of the aquarium, which faces the road and holds no water, can rupture in low temperatures, experts said. Ultraviolet rays and alternating temperatures have also damaged of the aquarium.

Regulations from Shanghai Municipal People's Government on the investigation and control of hidden dangers in production safety accidents will take effect on Jan 1. The regulations urge producers to establish their own rules on production safety.

Shanghai Municipal People's Government has investigated 137,472 enterprises this year, revealing 153,063 hidden dangers. Of those, 150,710 hidden dangers have been corrected. In 2011, the local government inspected 332,861 enterprises, finding 318,646 hidden dangers and correcting 309,683.

The local government has inspected about 1.03 million enterprises in the last six years, handling 1.28 million hidden safety production dangers. The government has also invested more than 3 billion yuan ($480 million) to promote production safety in all industries and areas.