Emergency services responded to a disturbance at a property on Grand Parade, Brighton, around 11 p.m. on Friday, August 23, following reports of a chemical incident involving ammonia.
The other two individuals remain in the hospital, though their injuries are not believed to be serious.
Sussex Police, along with fire and ambulance crews, quickly attended the scene to manage the situation. As a safety precaution, the building was evacuated, and a temporary road closure was enforced between the junctions of Richmond Parade and Morley Street.
Three individuals, two men and a woman, all known to each other, were arrested in connection with the incident and taken to the hospital for treatment. One of the men, a 32-year-old from Brighton, was later discharged and arrested on suspicion of causing grievous bodily harm with intent, criminal damage, and assaulting an emergency worker. He remains in police custody.

The other two individuals remain in the hospital, though their injuries are not believed to be serious.
Thanks to the swift response from the emergency services, the area was secured, and there is no ongoing risk to the public. Sussex Police have urged anyone with information regarding the incident to come forward by contacting them online or by calling 101, quoting serial 1526 of 23/08.