A study recently released by the Beijing Preventative Medical Resource Center shows that the bacteria that causes Legionnaire’s Disease can be found in 50% of Beijing’s top hotels.

Jinghua Times reported that Gao Xing, Deputy Director of the Beijing Preventative Medical Research Center, said that the study results will have some impact on government regulations. The hotels, where the bacteria has been found, will not be able to retain their five-star ranking.

The “Beijing Internal Environment Study” randomly chose more than 100 newly constructed or remodeled luxury hotels, offices, conference centers and science laboratories as well as 10,000 people as research subjects. The study, which took six years to complete, found Legionnella bacteria in 50% of the four-star and five-star hotels surveyed. Antibodies against the disease were also discovered in the blood of the hotel staff.

Other chemicals, such as aldehydes and benzene, were also detected at levels that threaten human health. These pollution sources can be building materials, paints, furniture and chemical cleaners.

Legionnaire’s disease is commonly associated with air-borne water droplets. It spreads quickly in warm, moist environments. In an indoor environment, it often grows in poorly maintained air-conditioning systems and enters the human body through inhalation.

The disease can cause infection of the upper-respiratory system, fever and headache. In the most serious cases, it can lead to difficulty in breathing, high fever, chest pain and kidney failure. In the United States, the disease is estimated to annually infect 25,000 people and to cause 4,000 deaths.