Nitrogen Refrigerated Liquid Hazchem Panel SignThe Nitrogen Refrigerated Liquid sign warns people about the presence of liquid nitrogen, which is a very cold substance used in certain industrial and scientific processes. The sign is used to keep people safe by alerting them to stay away from areas where liquid nitrogen is stored or being used, as it can cause severe cold burns or injuries. It is important to recognize this sign to avoid accidents in places where liquid nitrogen is handled.