Setting fire to shops and burning trash during protests in recent months are the major sources of cancer-causing dioxins found in the city’s air, Hong Kong environment minister has said, rejecting public speculations over tear gas releasing such toxins threatening public health. Secretary for the Environment Wong Kam-sing made his comments on Wednesday, after wide discussions over whether firing of tear gas led to the emission of dioxins in the city’s air. The discussions were sparked after a frontline reporter, who frequently covered protests that were tear-gassed by police, said last week that he was diagnosed with chloracne – a skin condition linked to exposure to dioxins. But Senior Superintendent Wong Wai-shun, who claimed the amount of tear gas he had breathed in was far more than anyone, said he had not developed any chloracne at all. A scientist said the government failed to address the concerns in time, prompting the rise in speculations among people. In a Legislative Council meeting, Wong said referring to experiences from around the world that the main sources of the emission of dioxins were from burning trash and trees. Tear gas fired as radicals attempt to escape Hong Kong university “In the recent situation in Hong Kong, we could see lots of burning of shops, cars and trash. We could see the area, duration and temperature of the burning,” Wong said. “If people are concerned about dioxins, these are exactly some of the major sources.” Wong said the Environmental Protection Department, which regularly monitored the level of dioxins in the air in the Central and Western district and Tsuen Wan, was currently collecting the samples for data this month. The result of the analysis is expected to be out in a few weeks. Speaking on the same occasion, Secretary for Food and Health Professor Sophia Chan Siu-chee said the Department of Health and the Poison Information Centre under the Hospital Authority had reviewed medical literature and scientific evidence on the links between tear gas and dioxins. “[They] have found no literature or scientific evidence on dioxin poisoning cases caused by the use of tear gas,” Chan said. What are the weapons police use on protesters, and how dangerous are they? Since the protests in Hong Kong broke out in June, police have fired more than 10,000 rounds of tear gas in various areas, including those with schools and health care facilities, to disperse protesters. People were worried about the health impact of the possible residue of tear gas, which prompted some schools to hire professional cleaning companies to do thorough clean-ups. The Environmental Protection Department did not find any anomalies in the levels of particulate matter recorded at stations near areas where tear gas had been fired since June. No abnormalities were found in any water quality monitoring stations during the same period either. While there had been calls from the public to disclose the models and the detailed composition of the tear gas rounds used by police, Chan said it would be “inappropriate” to disclose the procurement details of the equipment used by the force, as that would “affect police’s operational capability”. Professor Chan King-ming of Chinese University’s School of Life Sciences said there was no evidence suggesting tear gas would release dioxins. He said the main sources for Hongkongers taking in dioxins were from food, such as meat with higher contents of fats, milk and butter. He urged the public not to panic, but also said the government did not make concerted efforts to address the concerns of the public. “There isn’t a holistic approach to address the issue,” he said, adding concerned departments, such as the Environmental Protection Department and the Food and Environmental Hygiene Department, only handled issues that fell within their scopes.