Hong Kong’s rail operator urged police on Monday to consider the safety of passengers and staff after officers fired tear gas inside a subway station in an unprecedented deployment. Kwai Fong MTR station had reopened on Monday morning – just hours after its ground-level concourse was filled with the irritant smoke – and was packed with commuters and other passengers. Services were operating normally despite some traces of the intense violence still visible in the station, which sits on the Tsuen Wan line. Police ramp up force as Hong Kong rocked by more protest violence Some white powder was smeared on the floor while columns outside the station were turned into Lennon Walls, makeshift boards where protesters attach messages in support of the movement sparked by the now-shelved extradition bill. In a statement, MTR Corporation said it was “very regretful” the safety of passengers and its staff had been put at risk when police fired rounds of tear gas and rubber bullets. The company said it condemned the violence, also referring to protesters abusing fire extinguishers and damaging facilities. “Since there were passengers and MTR staff in the station, the actions and operation were threatening their safety,” the statement read. “We have raised our concerns with the police and urged them to consider the safety of passengers and MTR staff during law enforcement.” According to MTR Corp, the conflict between police and protesters at the station started at 8.15pm on Sunday, before officers started their dispersal operation in response to the throwing of objects, vandalism and misuse of fire extinguishers. The railway company said its staff activated the evacuation procedure once they saw smoke in the station. Train services to the station were halted while special trains were arranged so passengers could leave the station. As of 10.35pm, the station was closed for repair and examination after all passengers had left. On Sunday, an approved anti-government rally at Victoria Park in Causeway Bay once again escalated into a series of unauthorised protests across the city, as demonstrators continued to press their five demands, including setting up an independent inquiry committee against the police’s use of force and genuine universal suffrage. The protests originated from the now-abandoned extradition bill , which would have allowed criminal suspects to be extradited to mainland China. Protesters resumed their hit-and-run tactics on Sunday afternoon, besieging police stations and blocking roads across the city in areas including Tsim Sha Tsui, Tai Koo and North Point. After a crowd headed towards the nearby Kwai Chung Police Station for another flash mob-style siege, police started firing tear gas inside and outside Kwai Fong MTR station. As of 2.20pm on Monday, a total of 54 people, aged from eight to 56, were injured and sent to hospitals across the city. One man and one woman remained in serious condition. Why Hong Kong protesters view police as the enemy District council member Ng Kin-sing arrived outside the station early on Monday, where he suggested to residents they avoid the station because of the likely presence of potentially harmful chemical residue. “According to police’s guidelines, tear gas should not be fired in indoor areas. We are also concerned about the expired tear gas fired by them,” he said. “Some scientists in Venezuela have said firing it indoors may produce fatal chemicals. I think there is a big issue with what the police did.” Many elderly residents approached Ng to ask how safe the district was on Monday, while some criticised Ng for making a fuss out of nothing, as arguments broke out. Icarus Wong Ho-yin, a member of Civil Rights Observer, said that it was “very dangerous” for police to fire tear gas inside the station. “It violated the safety guidelines issued by the tear gas supplier,” Wong told RTHK on Monday morning. “Tear gas can only be used in outdoor area or spaces with good ventilation.” He said based on past experiences, tear gas could be lethal if it reaches a certain level of concentration. Emotions were running high with a resident seen embracing one of the youngsters in black clothes, who had a respirator. How Hong Kong’s young protesters built a reserve of protective gear A resident surnamed Wong also criticised police for neglecting the safety of citizens. “By firing tear gas into the station, the police was endangering many innocent residents who may not be protesters,” the 41-year-old accountant said. “I feel helpless and despair. I don’t know what we can do about this. Even though the protesters may be doing something wrong, fully equipped police should not use excessive force.” Tear gas might also cause long-term health damage to MTR staff and other workers such as shop assistants based in the station, Wong added. The warning written on gas cartridges and canisters typically states severe injury or death might result if they are fired directly at a person. The medical consequences of being exposed to the gas tended to be limited to minor skin inflammation, but people with pre-existing respiratory conditions, such as asthma, might need medical attention, according to an article issued in the Journal of the Royal Army Medical Corps in 2013. Carrie Lam reaches out to youth as city leaders close ranks on protest crisis Also outside the station, two youngsters, including 20-year-old student Wong Yan-tung, were seen distributing face masks since 7am on Monday, with posters and placards on the floor explaining what had happened the night before. “Firing tear gas inside the station is too much. We are here to give out masks to residents so that they can protect themselves from the chemical residue,” Wong Yan-tung said. “We also want them to know that youngsters are not rioters.” The student said some elderly people who supported them offered words of encouragement, while some attempted to give them money which they said they refused. State tabloid editor blasts Hong Kong mall for ‘kowtowing’ to protesters Anti-police sentiment has grown across much of Hong Kong over the past two months as sections of the public accused police of using excessive force at several protests. They were also accused of failing to protect residents when a violent mob, who initially targeted protesters returning from a march, attacked passengers indiscriminately at Yuen Long MTR station on July 21. However, large-scale rallies have also been held in Hong Kong, attracting hundreds of thousands, to showcase support for police and their handling of the protests.