At least seven workers were killed and two others injured today when they were exposed to toxic waste at a paper plant in central China, the latest industrial disaster in the communist nation still reeling under the country's worst industrial accident that killed 146 people.

The accident occurred after a worker fell into a pool of poisonous waste paper pulp and his colleagues rushed to help him. Several died while trying to rescue the worker.

The accident occurred at around noon in the city of Changde in Hunan Province, the local government said. They vowed to punish those who should be held accountable.

An investigation team has been sent to find out the cause of the accident, the Changde government said.

Meanwhile, the death toll from the Tianjin warehouse explosions today rose to 146, state-run Xinhua agency reported on China's worst industrial accident.

China's cabinet has promised a rigorous and thorough investigation into the deadly blasts that ripped through a warehouse on August 12 in the northern port city of Tianjin where hundreds of tonnes of toxic chemicals were stored, including around 700 tonnes of sodium cyanide.

While nearly 30 people are still missing, over 500 people remain in hospital after the huge explosions, which also seriously damaged two residential compounds nearby and gutted more than 3,000 new cars in a parking area close to the site.

The people killed in the blasts included 81 firefighters, seven policemen and 47 others.

China sacked the head of its work safety regulator for suspected corruption this week.

Yang Dongliang, currently under corruption investigation, was dismissed from his post as director of the State Administration of Work Safety.