Multiple people have been rushed to the hospital after two cleaning chemicals were mixed together at a Brooklyn spa, in New York.
The spa has now been evacuated. Reports claim that the chemicals mixed were acid and chlorine and patients are facing respiratory issues.
Officials said 20 people were inside the World Spa on McDonald Avenue at the time. The company clarified that the spa was closed at the time of the incident, and all people affected were staff members.
The incident happened at around 10pm local time (3am BST) on Wednesday but the spa remained closed on Thursday.
Crews from New York's Fire Department arrived at the scene and evaluated the situation. The issue was located in the basement of the building.
It was reported that they dealt with it by leaving any doors open for the spill to clear and evacuating the area.
Later reports suggested that five people were admitted to the Coney Island Hospital but none is in serious condition.
More than a dozen of the people that were near the source of the spill at the time required medical attention.
They were all employees of the "urban bathhouse", the luxury spa that opened just four months ago.
World Spa said in a statement: "We were deeply concerned by the incident that occurred at our spa in Brooklyn, NY, on Wednesday night.
"Our first priority is the safety and well-being of our customers and team.
"Because of the strict health and safety protocols we have in place, we acted quickly, contacting all relevant authorities to assess and address the situation.
"Our team fully cooperated with emergency services to ensure all affected staff received necessary medical attention.
"The incident occurred after the spa was closed, and no customers were affected.
"Upon inspection, all relevant agencies determined that the spa was safe to reopen.
"However, out of an abundance of caution, we have decided to stay closed for the day to ensure that our employee's needs are being met."
When chlorine bleach is mixed with an acid, chlorine gas is given off.
Chlorine gas and water combine to make hydrochloric and hypochlorous acids, the Washington State Department of Health warns on its website.
Exposure to chlorine gas, even at low levels and short periods of time, almost always irritates the mucous membranes (eyes, throat, and nose), and causes coughing and breathing problems, burning and watery eyes, and a runny nose.
Higher levels of exposure can cause chest pain, more severe breathing difficulties, vomiting, pneumonia, and fluid in the lungs.
Very high levels can cause death.
Chlorine can be absorbed through the skin, resulting in pain, inflammation, swelling, and blistering.
Hydrochloric acid also causes burns to the skin, eyes, nose, throat, mouth, and lungs.
The facilities of the luxury spa are spread across 50,000 square feet and include multiple treatment rooms.
World Spa opened on December 8, 2022, in Brooklyn.