Overview

This resource does not replace the Occupational Health and Safety Act (OHSA) and its regulations and should not be used as or considered legal advice. Health and safety inspectors apply and enforce these laws based upon the facts they find in a workplace.

In the food and beverage industry, specifically in restaurants, bars and ice cream serveries, using liquid nitrogen (LN2) has become popular for the preparation of novelty ice creams and cocktails.  LN2 is also used in healthcare settings, laboratories, and other workplaces.

LN2 is a cryogenic liquid commonly used for a variety of reasons, including:

  • food freezing
  • biological sample preservation
  • metal treatment
  • lesion removal (cryotherapy)

LN2 is nitrogen in a liquid state at extremely low temperature (-196°C) that expands rapidly at room temperature to nitrogen gas (1 litre of LN2 produces 700 litres of nitrogen gas).

The nitrogen gas produced is capable of displacing oxygen in air, which can lead to:

  • dizziness
  • nausea
  • vomiting
  • unconsciousness
  • death

Contact with liquid nitrogen can also cause severe burns, frostbite or tissue and eye damage. Bare skin can stick to objects cooled with LN2. Rubber, steel and other materials exposed to  LN2 can become brittle and shatter.

LN2 gas can be released into the air during liquid transfer as a result of leaking valves on storage containers and from open containers.  Explosions can occur if sealed storage containers are used or pressure release valves are blocked.

Ways to prevent injuries

The following are some safety measures that can help protect workers from hazards associated with liquid nitrogen:

  • Only use and store LN2 in well ventilated areas away from moisture and chemicals that can cause container corrosion.
  • Avoid skin and eye contact with LN2.
  • Use personal protective equipment, including:
    • loose fitting insulated or leather gloves
    • goggles
    • a face shield
    • long-sleeved shirt
    • pants without cuffs
    • closed-toe shoes or boots
  • Only use containers designed to store LN2 (for example, cryogenic storage tank or liquid nitrogen cylinder).
  • Always follow the manufacturer’s instructions and read and follow safety data sheets when working with LN2.
  • Dispense slowly from one container to another to prevent splashing, thermal effects and pressure build-up.
  • Use a handcart when moving containers to avoid splashes to the skin.

Occupational health and safety legal requirements

The Occupational Health and Safety Actsets out the general duties of workplace parties, describes ways of dealing with workplace hazards and provides for enforcement by the Ministry of Labour, Training and Skills Development where compliance is not achieved voluntarily. The general duties for employers, supervisors and workers may apply to protect workers from the hazards associated with LN2. The following are some examples of employers’ and supervisors’ general duties under the OHSA, as well as examples of precautions that may be reasonable depending on the circumstances.

Information and instruction

The OHSA requires employers to provide information, instruction, and supervision to a worker to protect their health or safety. Depending on the circumstances, this may include information and instruction on:

    • engineering controls
    • use of personal protective equipment (PPE)
    • safe work practices
    • emergency response procedures
    • first aid and
    • oxygen deficiency alarms

Every precaution reasonable in the circumstances

The OHSA also requires employers and supervisors to take every precaution reasonable in the circumstances for the protection of a worker.

Depending on the circumstances, this may include:

  • using containers designed to store LN2 (for example, cryogenic storage tank or liquid nitrogen cylinder).
  • supplying an oxygen deficiency alarm in areas where LN2 could displace oxygen and endanger a worker
  • The following are examples of requirements in regulations made under the OHSA that may apply to protect workers from hazards associated with LN2.

Regulation 851 – Industrial Establishments

Read Regulation 851 to review the provisions that may be applicable to hazards associated with LN2  in industrial establishments.

For example, under sections 45, 81, 82, 84, 127, 128, 130 and 138 of Regulation 851 – Industrial Establishments, there are requirements to

  • move things in a safe manner using precautions and safeguards, including personal protective equipment, so as not to endanger a worker
  • wear eye, foot and skin protection that is appropriate in the circumstances
  • adequately ventilate an industrial establishment by either natural or mechanical means so that the atmosphere does not endanger the health and safety of workers
  • provide replacement air to replace air exhausted, in accordance with certain prescribed requirements 
  • train a worker who may be exposed to a biological, chemical or physical agent, such as LN2, that may endanger a worker’s safety or health,
      • to use the precautions and procedures to be followed in the handling, use and storage of LN2
      • in the proper use and care of required PPE
      • in the proper use of emergency measures and procedures
  • protect a worker by mechanical ventilation so their health and safety is not endangered where the worker is likely to be exposed to an atmosphere at atmospheric pressure with an oxygen content of less than 19.5%. If it is not practicable to do so, the worker must be protected by air supplied breathing equipment, so their health and safety is not endangered.

Regulation 833 – Control of Exposure to Biological or Chemical Agents

Where it applies, employers have a duty under Regulation 833 - Control of Exposure to Biological or Chemical Agents to take all measures reasonably necessary in the circumstances to protect workers from exposure to a hazardous biological or chemical agent because of the storage, handling, processing, or use of the agent in the workplace.  The measures to be taken include the provision and use of:

    • substitution of the hazardous biological or chemical agent (where possible)
    • engineering controls
    • administrative controls, including work practices
    • hygiene facilities and practices
    • personal protective equipment (in specific circumstances as set out the regulation).

LN2 is a simple asphyxiant, therefore, the employer shall take all measures reasonably necessary in the circumstances to protect workers from exposure to an atmospheric oxygen level that is less than 19.5 per cent by volume.

An employer must protect workers from exposure to a hazardous biological or chemical agent, without requiring them to wear and use a respirator, unless specific circumstances set out in Regulation 833 apply, in which case an employer shall provide, and a worker shall wear and use, a respirator appropriate in the circumstances to protect the worker from exposure to the agent.  An employer who provides a worker with a respirator must comply with the Respiratory Protection Program provisions set out in Regulation 833 (sections 9 to 13). 

The above is not an exhaustive list of the requirements related to hazards associated with LN2. Read Regulation 833 for more information on requirements relevant to the hazards associated with LN2

Regulation 860 – Workplace Hazardous Materials Information System [WHMIS]

The Workplace Hazardous Materials Information System Regulation (R.R.O. 1990, Regulation 860) sets out in detail the employer's duties respecting labels and safety data sheets for hazardous products such as LN2 and prescribes the content and delivery of worker education programs.  Read Regulation 860 and Workplace Hazardous Materials Information System - A guide to the legislation for more information.