In 2009 a UK Health Protection Agency announcement changed analogue thermometers drastically. It announced that the traditional mercury thermometer could no longer be sold to the general public. This was due to the danger mercury presents to the environment and public health. ATP now stocks a range of mercury free thermometers containing liquid that is safe for the environment. Modern liquid thermometers contain one of many forms of alcohol or spirits. If broken or damaged these spirits will evaporate in a quick and harmless manner. The visibility of the alcohol is often improved by adding small amount of coloured dye to the solution. The temperature range of the thermometer varies dependant on the solution used.