Hong Kong health chief has said that there is no evidence to back the claims that tear gas poses major public health and environmental risks.

“We have conducted internal studies on whether tear gas will produce dioxin or cyanide,” Secretary for Food and Health Sophia Chan told the Legislative Council at a Q&A session on Wednesday. “We found no evidence based on existing research and academic literature that tear gas will generate dioxin.”

Sophia Chan. File Photo: GovHK.

Hong Kong police have fired thousands of rounds of tear gas since widespread protests broke out in June. The force said it used 1,567 rounds of tear gas last Wednesday alone in response to clashes that erupted across the territory.

The frequent use of tear gas by the Hong Kong police has prompted public health concerns. Last week, a Stand News journalist who has frequently reported from the protest frontlines said that he had been diagnosed with chloracne, a skin condition that has been linked directly to exposure to dioxin-like substances.

Chan said earlier this month that she had “limited” information about the chemical composition of the tear gas used by police. On Wednesday, lawmakers asked how the health chief could be sure that tear gas and its residue were harmless if she was not fully informed.

Medical sector lawmaker Pierre Chan has said that Queen Elizabeth Hospital medics – which has been affected by tear gas during recent protests – had doubts over the Health Department’s instructions on how to clean up after tear gas owing to a lack of transparency about its chemical composition.

Police fired tear gas during a protest on November 17, 2019. File photo: Inmediahk.net.

In response, Sophia Chan said that police could not disclose such information given its sensitive nature but cited the force as saying that the burning time of tear gas was short enough that any cyanide produced would quickly disperse in the air.

She said that although people had reported skin and respiratory problems after coming into contact with tear gas, the symptoms were not serious and typically disappeared within a short period of time.

Secretary for the Environment Wong Kam-sing said the major sources of dioxin globally were hill fires and waste burning in the open air. As such, he said, attention should be given to the actions of protesters, who have thrown Molotov cocktails, burned projectiles and set fire to stores and cars.

File Photo: inmediahk.net.

Hong Kong has been shaken by 25 weeks of protests triggered by a now-withdrawn extradition bill which would have enabled fugitive transfers to mainland China. The movement has since evolved into calls for democratic reform and accountability for the police handling of the crisis, as well as other demands.

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