Dry ice is used in a number of industries. For example, in food industry, products frozen with dry ice accumulate no moisture and are protected against spoilage (the emerging carbon dioxide gas forms the environment preventing microorganisms from multiplying, thus no mould or bacteria appear in products; moreover, in such environment insects and rodents are unable to survive). In medicine, dry ice is used to freeze and remove warts; in construction, it is used to loosen tiles from the surface they have been glued to (when frozen, the tiles crack); it is also used to fix valveless pipelines (water in pipelines is frozen); in laboratories, dry ice is used in organic solutions as a freezing agent for chemical reactions. Finally, it is a reliable fire fighting measure: several blocks of dry ice thrown into burning petrol extinguish fire.