An explosion rocked a pesticide factory in south China's Guangxi Zhuang Autonomous Region Monday afternoon, injuring three workers.

The blast occurred at 3:30 p.m. in the Jinsui Pesticide Factory along Yongbin Road in the region's capital city of Nanning, said rescuers.

The three injured were sent to a hospital, doctors said.

Firefighters put out a resulting fire around 6 p.m. The fire engulfed an area of 3,000 square meters and destroyed two warehouses.

Firefighting efforts were hampered by insufficient water supplies and a narrow road leading to the plant. Firefighters had to drain water from a nearby pond to douse the blaze.

Police have evacuated the factory's workers and cordoned off the plant, which has large stores of chemicals.

On-site tests show that two types of harmful gas, formaldehyde and phosphine, are being stored at the plant, said experts with the municipal Environmental Protection Bureau.

The gases are stored in low concentrations and do not pose a threat to public health, according to the bureau's experts. More tests will be conducted in the area.