On Friday morning, a group of volunteers cleaned up a subway station contaminated with tear-gas residue, fearing it could pose a health threat to commuters, particularly the elderly and children.

The operator of the MTR service had already cleaned up Kwai Fong MTR Station in the New Territories, where riot police fired tear gas to disperse protesters gathered there on Sunday, but people complained that they could still smell the gas days later.

Volunteers concerned about public safety wiped down the ticket machines and walls with damp cloths.

Volunteers clean up Kwai Fong MTR Station, where police fired tear gas in on Sunday
Photo: RTHK

The police force used “non-lethal weapons” to disperse anti-extradition bill protesters, regardless of where they were located, raising concerns about the potential impact on public health.

Police said around 1,000 tear-gas canisters were used between June 9 and August 4, and 800 rounds were deployed on August 5 alone during a citywide strike across eight districts.

No matter where the protesters gathered – on main roads, in alleys, subway stations and high-density residential areas, near homes for the elderly, and outside schools and kindergartens – the police used tear gas to disperse them. Locals are calling the police tactic a “tear-gas buffet.”

The police have repeatedly stated in their daily press briefings that officers are using “minimal force” in protest situations.

On Wednesday night in Kowloon’s Sham Shui Po, police confirmed they had fired 35 rounds of tear gas, with some landing in Ap Liu Street and Kweilin Street. It was the fourth time in 10 days that the district’s air was filled with tear gas.

Sham Shui Po, home to a diverse mix of new migrants from mainland China, working-class families, and senior citizens, is one of the most densely populated areas in Hong Kong.

Read: HK police fire tear-gas at the Hungry Ghosts

A noodle shop owner on Kweilin Street said his shop was filled with tear gas and that he had to abandon all his food at a cost of HK$3,000 (US$382), while another owner of an eatery on Fuk Wah Street said she had to close early, adding that she did not see any police officers check to see if there were any protesters in the street before firing  tear gas, Ming Pao Daily reported. She said there were no protesters in the vicinity.

A woman said her 88-year-old mother inhaled tear gas in her home and has suffered from a runny and bleeding nose since Sunday.

A father posted a photo of his seven-month-old son with rashes all over his body on Facebook. He said he forgot to clean clothes that were drying outside his home in Sham Shui Po. His son developed the rashes after wearing them.

A seven-month-old bay developed rashes after wearing clothes exposed to tear gas. Photo: Facebook / Justin Li

Lawmaker Kenneth Leung Kai-cheong expressed concern that residents’ health could be affected by tear-gas exposure. He urged the police force to minimize their use of tear gas and strictly follow the guidelines for its deployment.

However, police officers have fired tear gas indoors and in poorly ventilated areas, which is contrary to the supplier’s guidelines, the SCMP reported, citing Dr Anna Feigenbaum, author of the comprehensive 2017 book on the subject, Tear Gas.

“What makes tear gas legal to use is that protesters are always supposed to be able to get away from the smoke, and the smoke is always supposed to be able to evaporate and be ephemeral,” says Feigenbaum. But the problem in Hong Kong is the protesters are often hemmed in by cordons and barricades and can’t escape.

The type of chemical agent used by the local police, CS gas, is a fine powder or crystal that gets into clothes, causing ongoing irritation.

Medical personnel advise local residents to learn what to do if they are exposed to tear gas.

Go where there is fresh air, ideally to high ground. It the tear gas is used in a building, get out of it immediately. Keeping your arms outstretched will help rid your clothes of the gas.

Do not rub your eyes, and rinse away the chemical from your eyes and skin with large amounts of water or saline solution. Remove contaminated clothes and take a cold shower as soon as possible. The contaminated clothes should not be mixed with other garments when washed.

More unrest expected

Meanwhile, more protests and rallies are expected this weekend.

On Saturday, the education sector will begin a march at 11 am in Chater Garden in Central and walk to Government House, where the chief executive, Carrie Lam lives, with the formal approval of the police. However, a proposal for a march in the Hum Hom and Kowloon City area was rejected due to safety concerns.

Civil Human Rights Front, the organizer of the previous million-people marches in June, are permitted to hold a rally in Victoria Park in Causeway Bay at 3 pm. The police rejected their proposal for a march to Central.

The police said at a press conference on Friday that if no one clashes with the police, officers would not fire tear gas.

The force also said the use of the new water cannon-equipped anti-riot vehicles would be restricted to situations where there are casualties, large-scale property damage, or obstacles on main roads.

Meanwhile, the police will be sending out SMS public safety messages to the public during mass demonstrations.