Rubber boots and waders are worn over socks to keep feet dry when they are in continuous contact with water or chemicals. Food-processing boots resist animal fluid and chemicals encountered in food manufacturing. Oil, gas, and mining boots are resistant to chemicals and have special safety features, such as toe caps, that protect feet from hazards encountered by workers in mines, oil fields, and petrochemical plants. Hazardous materials (hazmat) boots protect feet from corrosive chemicals and are often used by emergency response teams or workers in chemical processing. Farming, agriculture, and fishery boots are made of materials that resist damage caused by animal waste, chemicals, and liquids in fisheries and shrimping. Winter, cold-insulated boots keep feet warm and dry in wet and freezing temperatures. Waders extend to the hip or chest to keep feet dry when working in deep water.