After years of suffering , his father died of lung cancer in 2014, which Li believes was caused by the cadmium poisoning.

Hunan province is home to many of China’s industrial plants and there have been hundreds of similar cases.

Cadmium is a toxic heavy metal and breathing air with very high levels of cadmium can prove fatal.

Long-term exposure to lower levels of cadmium can cause damage to kidneys, lungs, bones and the intestinal tract as well as causing cancer.

In 2013, an investigation found that rice grown in the province contained excessive levels of the industrial chemical.

In the latest case, cadmium produced at an illegal factory in the farming town of Chaensi started leaking into the soil surrounding the area, contaminating local farmland.

In February last year, a few months after the plant started operating, locals complained they were being poisoned.

Investigators found that soil samples from the are continued up to 1,040 times the permitted levels of cadmium.

In June the plant was closed by the authorities, who seized more than 10 tonnes of cadmium alloys, and 10 people arrested.

On Wednesday the news portal Thepaper.cn reported that they had been given prison sentences, without giving further details, and fined over 1 million yuan (US$159,000) to compensate their victims.

But Li said that for most victims of cadmium poisoning no sentence and fine is sufficient. “Their life will never be the same again, and polluted farmlands cannot be restored.”

The metal poisoning scandal in his home was widely reported at the time after a large protest by residents attracted the media’s attention.

The case centred on the Xianghe chemical plant, which opened in 2004, ostensibly to make an animal-feed additive but in reality was producing indium – a toxic metal used in solar panels and LCDs.

The factory’s discharges of untreated effluent containing cadmium and indium poisoned wells and seeped into the soil of farmers’ fields, but environmental protections officials were bribed to turn a blind eye to its illegal operations and ignored villagers’ complaints for years.

Their plight only came to the public’s attention in July 2009 after they staged a protest about five residents who had died from cadmium poisoning and laid siege to government buildings.

Faced with mounting public anger, the authorities promised to act. The factory manager was arrested, the plant razed to the ground and some local officials were fired.

The authorities subsequently admitted five people had died from cadmium poisoning, and medical examinations of people living within 1.2 kilometres (1,300 yards) of the site found almost 600 had been seriously affected by exposure to zinc and cadmium.

The local government offered one-off compensation of 3,800 yuan for all residents living within a 500 metre radius of the site – regardless of their health status – as well as a one-off payment of 1,200 yuan for every 667 square metres of farmland they owned.

But villagers said the true number of people dangerously exposed was or three times higher than the official numbers.

Locals have since complained that officials remain indifferent to a growing number of cancer deaths – including Li’s father that they blame on the poisoning – and complain that their land remains contaminated.

“We are still suffering but already forgotten by the outside world,” Li said.

“New cadmium poisonings are still happening in the province. It seems like it will never end.”