NANJING - Six butchers in East China's Jiangsu province have received jail terms ranging from three-and-a-half to four years over a chemical-tainted pork scandal reported in March, court authorities said Wednesday.

The six were convicted of harming public safety by producing and selling pork tainted with clenbuterol, a carcinogenic chemical added to pig feed to produce leaner pork, the provincial higher people's court said in a press release.

It said their jail terms were handed down by a local court in Nanjing on December 13 and the ruling went into effect as of Tuesday, as none of them had appealed within the given two weeks.

The court ruling also included fines ranging from 40,000 to 50,000 yuan ($6,340 to $7,925) each.

The six butchers, who worked at a Nanjing slaughter house, admitted they had bought live pigs from central Henan province, slaughtered and sold the pork earlier this year, even though they knew the pork had been tainted by clenbuterol, the document said.

All six butchers signed contracts with the slaughterhouse in March 2009, vowing they would not sell clenbuterol-tainted pork, it said.

The pork scandal was reported in March, after a sample test by local authorities found 132 out of 134 live pigs at the slaughterhouse had been tainted by clenbuterol.

Cai Shaogang, an official with the provincial higher court, said several others, including government employees, in Nanjing were being tried over the pork scandal. "We'll keep the public informed once their rulings are made."

As of the end of November, the pork scandal had landed at least 113 people, including 77 government employees, in jail in Henan province, China's leading agricultural base.

Clenbuterol is banned as a livestock feed additive as it can cause nausea, dizziness, headaches and heart palpitations in humans.