Polytechnic University says its campus is safe

Police fire tear gas outside the Polytechnic University during clashes with protesters in November. File photo: Shutterstock

The Polytechnic University said on Friday that independent testing to examine tear gas residue at the campus had found that it was below international recommended thresholds.



It said in a statement that independent laboratories had taken samples on campus, including air, water, soil and surface wipe samples.



It said the samples were analysed, and the test results for dioxins, total polychlorinated niphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and other ingredients fell below the thresholds set by "international organisations".



"Also, according to the test results for soil, tap water, and surface wipes samples, the aforementioned contaminants are well below their respective reference/reporting limits listed in the authoritative documents of relevant Hong Kong or international authorities/institutions," the university said.



In an article late last year in The Lancet, researchers from the Chinese University of Hong Kong (CUHK) called for government-led decontamination efforts in areas where tear gas has been dispersed, including residential neighborhoods and commercial shopping centres.



Some journalists have complained of health problems after being exposed to tear gas while covering months of unrest, raising concerns at the level of dioxins in the air after thousands of rounds were discharged over months of protest.



However, police have responded by saying there are multiple sources of dioxin in the environment, from vehicle pollutants to rioters burning plastics.