A blast at a power plant in central China killed at least 21 people and injured five on Thursday, the eve of the first anniversary marking massive Tianjin explosions that have spurred government efforts to improve industrial safety.

The power plant blast in Dangyang city in central Hubei province took place around 3:20pm on Thursday, when a high-pressure steam pipe exploded, the official Xinhua news agency said.

The State Administration of Work Safety has dispatched a team to the plant to bolster local rescue efforts and to investigate the accident, state-owned China News Service reported, citing Yang Huanning, head of the administration.

Yang said there were lessons to be drawn from the incident to prevent similar mishaps from recurring.

Deadly accidents are relatively common at industrial plants in China, and anger over lax standards is growing after three decades of swift economic growth marred by incidents from mining disasters to factory fires.

China has vowed to improve safety at such facilities.

President Xi Jinping has said authorities would learn the lessons paid for with blood after chemical blasts in the port city of Tianjin on Aug 12 last year killed more than 170 people.

Binhai New Area in Tianjin has completely overhauled 583 dangerous chemicals companies, Xinhua reported on Thursday, with 68 firms ordered to shut or relocate.

A year later, excavators are still working to clear rubble from the disaster site, pointing to the scale of the destruction, while survivors of the blast grieve.