After Hong Kong Police Use Tear Gas on Campus, Health Chief Claims 'No Evidence' Chemical Poses Health Risks

Hong Kong's top health official has claimed that tear gas poses no major risk to public health, days after police in the city reportedly used the chemical weapon to combat protesters at a university.

Secretary for Food and Health Sofia Chan claimed during a government meeting Wednesday that although protesters exposed to tear gas have reported serious respiratory and skin issues, the effects of the chemical don't last long or cause significant damage.

Concerns about health risks were heightened last week after a Hong Kong journalist who had been exposed to tear gas claimed to be diagnosed with chloracne, a serious skin condition that is caused by exposure to the toxic chemical pollutant dioxin. Although not typically present in common forms of tear gas, many in the city now believe that the tear gas used by Hong Kong police contains the substance, which causes serious and long-lasting health effects.

Hong Kong protestors
Hong Kong protesters pictured at a pro-democracy rally on November 12, after police showered the group with tear gas. DALE DE LA REY/Getty

Under certain conditions, common forms of tear gas are said to be capable of forming cyanide and a dioxin-like substance, but Chan claims that the gas used in Hong Kong is not capable of producing the potentially deadly chemicals.

"We have conducted internal studies on whether tear gas will produce dioxin or cyanide," said Chan. "We found no evidence based on existing research and academic literature that tear gas will generate dioxin."

Chinese Secretary for the Environment Wong Kam-sing has claimed that dioxin in city's air is unrelated to the chemical riot control agent being used by police but is instead coming from fires burning on hills and in trash piles. He argues that protesters throwing "Molotov cocktails" could be responsible.

Police were said to have used tear gas on a group of protesters at the Hong Kong Polytechnic University on Monday, after the group had taken control of the campus and kept authorities at bay for several days. During the police siege of the campus, Hong Kong authorities claimed the protesters were "criminals" who deserved harsh treatment.

"These rioters, they are also criminals. They have to face the consequences of their acts," said police commander Cheuk Hau-yip to CBS. "Other than coming out to surrender, I don't see, at the moment, there's any viable option for them."

Hong Kong police have used thousands of rounds of tear gas over the last several months. Large scale protesting began in the city in June, over a proposed law that would have allowed people accused of a crime to be extradited to mainland China. The law was withdrawn but protests have continued and evolved into a movement seeking greater democracy and a reduction of what they claim is police brutality in former British colony. Many of the demonstrators claim their rights have been eroding since China regained control in 1997.

The U.S. Centers for Disease Control and Prevention (CDC) says many of the effects of common tear gas can be temporary, but the extent of damage depends on several factors including the amount of chemical a person is exposed to, and the length of time they are exposed. Exposure to a larger amount or a longer exposure period can result in severe effects including glaucoma and blindness. The CDC claims the most severe effects potentially include death caused by respiratory failure or chemical burns to the lungs or throat.