Tokyo, Sep 12 (IANS): An explosion took place on Thursday at a sewage facility in Osaka, reportedly injuring four male workers on site, according to local authorities.

At 12:15 p.m. local time, the blast occurred at Nagahori Pumping Station in the Japanese city's Nishi Ward, and was reported by a passerby, the fire department said.

The explosion occurred in a temporary water storage area inside the facility where the workers were performing maintenance, Xinhua news agency reported.

A total of 12 fire trucks were dispatched to the scene, and the blaze was contained within 15 minutes. According to Osaka Prefectural Police, four male workers in their 30s and 40s were injured, with three transported to hospital. All were conscious with non-life-threatening injuries.

The explosion caused a strong burning odour in the area, and the fence in front of the facility was heavily damaged. A nearby convenience store worker reported hearing several loud boom sounds and feeling a strong shake inside the store, describing the incident as shocking and sudden.

The exact cause of the explosion is still under investigation.