INTRODUCTION : You would recall from your study of Unit 11 that LPG (liquefied petroleum gas) and other compressed gases can pose a danger in the lab. The gas (LPG) supply distribution has been covered in the previous exercise and the main danger associated with it i.e. fire is dealt in the next exercise. In the context of compressed gases you had learnt about the colour codes used to indicate the content and nature of the gas in the cylinder. You would have realised that these cylinders being heavy objects are potential mechanical hazards. The - hazards of gas cylinders are further increased by the toxic/ reactive properties of their contents. You have learnt about the precautions to be observed in the storage and handling of these gas cylinders. In this exercise you will be using the gas cylinder colour codes to identify the contents of the gas cylinder and study about their storage and handling in the lab.