TIANJIN - Investigators in Tianjin Municipality have announced a warehouse which exploded on Monday night was in violation of rent regulations.

The explosion occurred around 9:40 pm Monday at a warehouse owned by Tianjin Yong Sheng Fine Chemical Co, Ltd at Xiditou Township of Beichen District. The flames were put out around 2:33 am early Tuesday.

An initial investigation showed the company, registered in Tianjin municipality, rented a private 700-square-meter warehouse in the northern suburbs from a local villager, according to the publicity department of Beichen district.

"Such chemical warehouses should be registered with the government, but clearly they had failed to do so," an official with the department said.

The warehouse stored about 3,000 kilograms of alcohol, 1,000 kilograms of acetic aid, 800 kilograms of glycerinum, 500 kilograms of sodium hydroxide and 500 kilograms of potassium hydroxide, according to the district environment protection bureau.

Alcohol, together with acetic aid and glycerinum, are inflammable chemicals.

Data from the local environmental protection bureau showed no ammonia and hydrothion has been detected, and four milligrams per cubic meter of carbon monoxide was found, measuring up to air quality standards.

Further investigation is underway.