A common means of cooling and preserving items in the food and beverage industry, liquid nitrogen is commonly administered for such purposes. (It was also implied as a key ingredient in a great special effects action scene in Terminator 2: Judgement Day, albeit unrealistic.)

However, it's important to remember that liquid nitrogen is a cryogenic liquid - and cryogenic liquids come with their fair share of health and safety hazards. In this post, we'll discuss just what liquid nitrogen is and its health and safety hazards. We'll also discuss why liquid nitrogen safety clothing and PPE are so important, among handling and storage best practices. Read on to learn more.

What is Liquid Nitrogen?

As we noted in the opening, liquid nitrogen is a cryogenic liquid - and cryogenic liquids are extremely cold in the liquid state, yet at average temperature when in the gaseous state. That's why it's so commonly used to freeze food and preserve other items. However, it's this extreme cold in the liquid state that also poses certain hazards. Other hazards are present when it's in the gaseous state. These hazards include:

  • Extreme cold: With liquid nitrogen, this can have the same effect as a thermal burn. Prolonged exposure can lead to frostbite and possibly even lead to blood clotting in the affected area.
  • Asphyxiation: This is most common in liquid nitrogen's gaseous state. In the gaseous state, liquid nitrogen doesn't easily disperse and can displace air in a confined environment. Without air or oxygen, there's a risk of asphyxiation.
  • Toxicity: Cryogenic liquids in the gaseous state can be toxic.

Other hazards of cryogenic liquids include:

  • Fire hazard
  • Oxygen-enriched air
  • Liquid oxygen hazard
  • Embrittlement

Liquid Nitrogen Uses

Liquid nitrogen is commonly used in the food and beverage industry to cool and preserve food items. It can also be used as a tool to rapidly cool beverages. It's also commonly used in the medical industry, manufacturing environments, construction and more. Here's an overview of some of the uses of liquid nitrogen beyond the food and beverage industry:

  • Dermatologists may use liquid nitrogen to remove skin abnormalities.
  • It can be used to quickly cool superconductors.
  • It can help preserve blood.
  • It can help preserve biological samples, including eggs, sperm and more.
  • It's involved in the use of cryosurgery, or removing dead cells from the brain.
  • Construction workers may use liquid nitrogen to temporarily freeze water pipes to stop the flow of water if they're unable to find a valve to turn the water supply off.
  • It's often used to either protect materials from oxidation or shield materials from oxygen exposure.

Dangers of Liquid Nitrogen

As noted in the above section, hazards include extreme cold, asphyxiation and toxicity. However, there are various other dangers associated with cryogenic liquids that are worth mentioning as well. These include:

  • Adhesion: Cold surfaces containing liquid nitrogen or parts that have been treated with liquid nitrogen can sometimes cause the skin to stick to them upon contact. It's natural to try to remove the skin from these surfaces upon contact, which can result in skin tearing. We've all seen movies where someone is dared to lick a cold pole, only to have their tongue stick to it. Liquid nitrogen-containing parts or treated surfaces can often have a similar effect on the skin, should they come into contact with it.
  • Boiling: Cryogenic liquids often boil after they're added to a warm container.
  • Explosions: As liquid nitrogen vaporizes, any significant liquid-to-gas ratio may result in significant pressure changes. Noting that cryogenic liquids may also condense moisture from the air, thereby freezing and blocking storage vessels, explosions may occur as a result of these trapped, pressurized gases.
  • Embrittlement: While often not a health and safety threat, embrittlement is characterized as a general hazard of liquid nitrogen, particularly with rubber or plastic parts. When working with these materials and using liquid nitrogen, they may become very brittle and easily break. They may pose a threat if they're being used as part of a greater assembly.

How to Safely Handle Liquid Nitrogen

There are two elements to the safe handling of liquid nitrogen. There's a PPE component, which involves liquid nitrogen protective clothing when working with cryogenic liquids. And there's also a safe storage aspect. In this section, we'll cover both of these. Let's start with liquid nitrogen safety clothing and other PPE.


When you're working with liquid nitrogen, you should ensure your hands and eyes are protected. You should also ensure you're wearing appropriate clothing to protect your skin. Here's an overview of what to wear when handling cryogenic liquids:

  • Loose-fitting insulated or leather gloves can be easily removed if the cryogenic liquid is spilled onto them. Don't wear rubber gloves, as they'll harden and become brittle if they come into contact with liquid nitrogen.
  • Face shields or goggles provide appropriate eye protection from cryogenic liquids. It's suggested that these pieces are worn together to maximize facial protection. Don't wear safety glasses, as they won't protect your face. Liquids may also still get around safety glasses and into the eyes.
  • Wear closed-toe shoes and cuffed pants that fit over the top of the shoes. Long-sleeve shirts should be worn to protect the arms. Consider wearing an apron and lab coat when working with such liquids to enhance bodily protection. Try not to leave any skin exposed and don't wear watches or jewelry.

In addition to wearing the right PPE, anyone who handles liquid nitrogen should be qualified to do so. Safety training is imperative when working with cryogenic liquids. So is ensuring such handling is carried out in the right environment. For instance, well-ventilated areas are a must so they don't create an asphyxiation hazard in its gaseous state.

Safe Storage

Cryogenic liquids are often stored in vessels known as dewar containers, which feature vacuum space between a cold liquid and the outside walls of a vessel. In addition to wearing the right PPE when working with and storing cryogenic liquids, it's best to schedule dewar fills during normal business hours when there are other workers available to assist. Here's a closer look at best practices for storing cryogenic liquids in dewars:

  • Ensure liquid nitrogen is stored in a well-ventilated area to prevent oxygen deficiency and reduce any hazards. Never store liquid nitrogen in a confined space.
  • Only approved storage vessels should be used for such purposes. Approved storage vessels must have pressure relief valves.
  • Don't tinker with pressure relief valves. Adjusting, blocking or plugging a valve can create a dangerous situation.
  • Minimize the risk of ice plug formation in storage containers. Containers should also be occasionally checked for ice plugs and appropriate corrective action should be taken. They should also be periodically inspected for other defects.
  • Don't keep heat sources near areas where cryogenic liquids are stored.
  • Refrain from using cryogens or dry ice in walk-in cold rooms. Sufficient air may be lacking and the space could become oxygen deficient.
  • Containers should be free of oil, grease, dirt, and other contaminants which could present a fire hazard upon contact with any liquid oxygen. Containers should also be stored in an upright position. They should never be stored on their side or rolled.

While liquid nitrogen is frequently used in various industries, it should not be handled by individuals without proper training. That's why it's important to have a robust safety plan in place and the right PPE for workers to wear when handling cryogenic liquids. Now's the time to review your safety plan to ensure workers are empowered with the right information and supplies to safely handle liquid nitrogen.