GBL (Gamma-Butyrolactone)

Authorities in Cyprus say a chemical known as GBL, a substance normally used in industrial cleaning and manufacturing, was found in a water cooler linked to the death of a 78-year-old man and the hospitalization of four others in the coastal city of Larnaca.

Health officials said the condition of the four hospitalized patients continues to improve. One of them, who had been receiving breathing support in intensive care, has been taken off a ventilator and remains under close medical supervision. Doctors described the development as encouraging, noting that the other three patients are also improving day by day.

Laboratory tests by the State Chemical Laboratory confirmed the presence of GBL, or gamma-butyrolactone, a colorless and odorless liquid that can be dangerous if swallowed. Once inside the body, the substance is quickly converted into a powerful depressant that slows the brain and breathing, making overdoses difficult to treat and potentially fatal.

Police said the test results are critical to their investigation, which is now focused on determining how the chemical entered the water cooler from which the victims drank. Officers are continuing to take statements from relatives and others who were present at the residence when the incident occurred.

Authorities said no additional people have been identified as having consumed water from the same cooler beyond the four patients currently hospitalized.

Officials declined to say whether the case involves criminal activity, describing the investigation as sensitive and dependent on scientific findings that are still being reviewed. Toxicology and other specialized tests are ongoing and may take time to complete.