Cryogenic liquids are extremely cold substances that require special safety precautions. Only individuals who are fully aware of the potential hazards and unique properties of these materials should handle them. Improper handling can lead to serious injuries, including frostbite, tissue damage, and respiratory issues caused by oxygen deficiency. Comprehensive safety measures are therefore essential. Key precautions include:

Cryogenic liquids are substances that exist in a liquid state at temperatures below –150 °C. These ultra-low temperatures cause extraordinary physical effects, significantly influencing the behavior of materials and gases:

• High Evaporation Rates: Even minimal heat input causes rapid vaporization, which can result in significant pressure buildup in sealed systems.

• Oxygen Displacement: Vaporized gases displace atmospheric oxygen. In poorly ventilated areas, this can lead to asphyxiation without warning signs such as odor or irritation.

• Fire and Explosion Hazards: Liquid oxygen increases the flammability of many materials, while cryogenic hydrogen is highly explosive.

• Cold Burns and Frostbite: Even brief skin contact can cause severe tissue damage. Dripping liquids may enter shoes or sleeves, causing injury.

A solid understanding of the behavior and interactions of cryogenic media is essential for all users.

Cryogenic liquids may only be stored and transported in designated, certified containers that can withstand the specific physical properties of the substance:

• Dewar Vessels: Double-walled, vacuum-insulated containers with pressure-relief safety features. Must not be filled above the recommended level.

• Labeling Requirements: Containers must be clearly and permanently labeled in accordance with applicable regulations. The type and extent of labeling depend on the specific medium, its application, and relevant standards.

• Transport Safety: Mobile transport is subject to hazardous materials regulations (e.g., ADR), must be secured against shocks and tipping, and carried out only by trained personnel.

• Storage Conditions: Store only in well-ventilated areas, away from heat sources, ignition points, or flammable materials. Temperature sensors and gas detectors are mandatory.

Containers must be regularly inspected and maintained by qualified personnel to detect embrittlement, leaks, or mechanical damage at an early stage.

Transferring cryogenic liquids involves heightened risks of splashes, explosive vaporization, or material failure. The following safety rules apply:

• Use Pre-Cooled Target Containers: To avoid sudden boiling upon contact with warm surfaces and reduce vaporization, always transfer into pre-cooled containers whenever possible.

• Slow, Controlled Transfer: Prevents pressure and temperature spikes. Only trained personnel should perform the transfer.

• Use Suitable Equipment: Hoses, fittings, and adapters must be rated for cryogenic temperatures (e.g., stainless steel, PTFE) and pressure-resistant.

• Ensure Proper Venting: Never fill into closed systems. Each system requires controlled pressure relief.

Additionally, a risk assessment and authorization must be completed prior to each transfer. Emergency equipment such as shut-off valves, safety showers, and alarms must be within reach.

Uncontrolled release of cryogenic gases can quickly displace oxygen in the air. Key measures for ensuring air safety include:

• Monitoring Oxygen Levels: Work areas involving cryogenic liquids must be equipped with reliable oxygen sensors that monitor concentration changes in real time.

• Ensure Sufficient Ventilation: Effective mechanical ventilation is essential in these areas. It should provide continuous airflow and sufficient air exchange to prevent gas accumulation and reduce the risk of oxygen deficiency.

• Regular Maintenance of Ventilation Systems: All ventilation equipment must be regularly serviced and checked for functionality. Malfunctioning systems greatly reduce safety and can lead to dangerous situations.

Air monitoring is not an optional extra but a critical safety measure. Only through continuous oxygen level monitoring and effective ventilation can hazards be detected early and serious incidents prevented.

Safe handling of cryogenic liquids requires sound knowledge and regular training. Only properly trained personnel are permitted to work with these substances—this is not only a regulation but a fundamental safety requirement.

• Conduct Regular Training: All employees working with cryogenic liquids must be routinely trained and informed about potential hazards, protective measures, and emergency procedures.

• Provide Practical Training: In addition to theory, hands-on training is essential—e.g., safe transferring, donning PPE, and responding to alarms.

• Promote Understanding of Safety Protocols: Training content should be clear, practical, and relevant. Questions and feedback from everyday work are encouraged.

• Ensure Proper Documentation: All training sessions must be documented. This provides a legal record of who received training and when.

Only well-trained and informed staff can handle cryogenic liquids safely and responsibly. Training must therefore be an ongoing part of the safety culture, not a one-time event.

In an emergency, every second counts. A well-prepared emergency response and clearly defined first-aid measures can minimize injury and save lives.

• Maintain First-Aid Equipment: Emergency showers, eye wash stations, first-aid kits, and oxygen monitoring devices must always be functional and easily accessible.

• Response to Cold Exposure: In cases of frostbite or cold injury, do not rub the affected area. Instead, rinse with lukewarm (not hot) water and seek medical attention immediately.

• Recognize Oxygen Deficiency: At the first signs of oxygen displacement (e.g., dizziness, disorientation, shortness of breath), evacuate the danger zone and move affected individuals to fresh air. In case of unconsciousness: call emergency services and initiate resuscitation if necessary.

• Practice Alarm and Evacuation Procedures: All employees must be familiar with internal alarm protocols, emergency numbers, and evacuation routes. Regular drills improve confidence and response in real situations.

A structured emergency response ensures fast, calm, and effective action during critical incidents—minimizing health impacts and keeping situations under control.

Cryogenic liquids offer many useful applications but also pose significant risks. Anyone working with them bears responsibility—for their own safety, that of their colleagues, and the safety of their environment. The key to safe handling lies in solid knowledge, proper protective measures, and structured emergency procedures. Safety is not a one-time achievement, but an ongoing process. Only those who stay vigilant and follow all safety rules consistently can prevent accidents and ensure a safe workplace.