The Ministry of Emergency Management said all workers in high-risk industries will need to have vocational certificates by the end of 2021 because low-skilled workers are one of the main causes of industrial accidents.

A guideline released by the ministry and four other State organs on Nov 1 said workers in fields like mining, chemical production and fireworks manufacturing should receive training from employers or vocational schools before beginning work.

The ministry said migrant workers, usually poorly educated, account for the majority of employees in high-risk industries.

Of the 18 million employees in such industries, about 34 percent have a junior high school education or below, and only around 20 percent have received formal vocational skills training.

In small workshops, most frontline operators are migrant workers, and accidents in such enterprises account for more than 80 percent of those in high-risk industries.

In March, an explosion at a chemical factory in Yancheng, Jiangsu province, killed at least 78 people. An earlier report by the central government found that nearly all the workers lacked vocational qualifications.

Pei Wentian, a senior official with the ministry, said safety training is globally considered one of the four pillars of safety supervision, along with legislation, enforcement and insurance.

"However, problems including lack of training, improper training and low training standards are prominent in China's high-risk industries," he said.

"High work intensity, a poor work environment and safety risks, mean professionals don't want to work there, so training the workers who are currently employed is necessary."

According to the guideline, each worker will need to undertake at least 72 hours of compulsory training on work safety, and they will only be allowed to work after passing an exam.

Employers should promote the training plan, the guideline said. Enterprises should set up training centers, and prepare courses and assessment standards based on their own situations.

Pei said the ministry would give financial support to small and medium-sized enterprises so they could buy training services from third-party institutions.

"Ensuring work safety is not a short-term task," he said. "It will take a long time for us to investigate various reasons behind the scenes, not just confined to training."