A recent experiment has found that of three types of plastic, vinyl chloride produces the largest amount of dioxin when burned and nonplastic substances produce more dioxin when burned together with chlorine compounds, according to researchers.

The test was conducted by a research group formed jointly by the Gifu Prefectural Institute of Health and Environmental Sciences and the National Institute for Environmental Studies. The results were announced Tuesday to an environmental science conference in Sapporo.

Scientists already know that dioxin, a carcinogen, is produced through burning, particularly plastics, but it is unclear how much dioxin is produced by each substance.

The experiments could prove useful in efforts to reduce the amount of dioxin being released into the environment.