Period 6 element point of −38.83 °C and boiling point of 356.73 °C, mercury has one of the narrowest ranges of its liquid state of any metal. Mercury occurs in deposits throughout the world mostly as cinnabar (mercuric sulfide). The red pigment vermilion is mostly obtained by reduction from cinnabar. Cinnabar is highly toxic by ingestion or inhalation of the dust. Mercury poisoning can also result from exposure to water-soluble forms of mercury (such as mercuric chloride or methylmercury), inhalation of mercury vapor, or eating seafood contaminated with mercury. Mercury is used in thermometers, barometers, manometers, sphygmomanometers, float valves, mercury switches, and other
Sarah Liao annual air monitoring project. This program was designed to provide extensive background environmental data, which continued for five years. She then spent over seven years establishing and administering the program on Environmental Health & Safety at the University. Another area of work was the management of toxic and hazardous materials (chemical and biological) used in the University, including the procurement, storage, delivery, use, pre-disposal treatment and final disposal of these substances. At the same time she conducted large scale studies relating to workplace health and safety, hazard identification, risk assessment and environmental problems in a range of Hong Kong industries.