If you artificially inseminate (abbreviated as AI), you have been exposed to liquid nitrogen. Unfortunately, it is human nature to become careless when you become familiar with something. This holds true with liquid nitrogen. Liquid nitrogen is commonly used to freeze and store specimens in labs. It is also used in semen storage tanks to keep straws of sperm frozen. We also see it used to make ice cream. Even though it is commonly used, it is critical to follow safety procedures, because it is dangerous.
Liquid Nitrogen is Extremely Cold
Liquid nitrogen is extremely cold at -320 degrees Fahrenheit, causing exposed skin to burn and causing white blisters. This is the most-common experience people have when handling liquid nitrogen. Individuals handling liquid nitrogen should wear gloves and proper footwear. When liquid nitrogen has the opportunity to sit on the skin, burning occurs. Therefore, select gloves and shoes that are not permeable. Individuals that handle liquid nitrogen frequently become accustomed to the cold. Even though individuals become comfortable with the extreme cold, do not become careless with the other safety precautions.
Liquid Nitrogen Can Cause Asphyxiation
Liquid nitrogen can steal oxygen from the air, causing asphyxiation (suffocation), causing a person to become unconscious and possibly die. Liquid nitrogen has the scary ability to expand by 700 times in volume when it evaporates. Even more scary, liquid nitrogen gas is colorless and odorless, allowing it to be an easy killer. Therefore, it is extremely important for proper ventilation, since a plugged tank with the lid down will release nitrogen evaporation.
A study conducted by American Breeders Association (abbreviated as ABS) cryogenic team in DeForest, Wisconsin has compelling data to show the dangers of liquid nitrogen during the Applied Reproductive Strategies in Beef Cattle Conference in Cheyenne, Wyoming.
- When placing 10 tanks newly filled into a 12 by 15 (1440 cubic feet) enclosed nonventilated room, it took 18 minutes for the air to become unsafe for human occupancy (19.5%); and as the tanks sat, the oxygen level continued to decrease slowly.
- In another study, ABS placed two newly filled tanks into the back seat of a crew cab truck. It took 3 minutes for the cab to become unsafe for human occupancy. One hour later, the level of oxygen had depleted to only 14.7% oxygen.
- ABS also simulated a tank tipping over in a back seat of a Ford crew cab truck, and in less than 1 minute, the oxygen level in the cab had reached below 18.3% oxygen. Within 10 minutes the level had depleted to only 9.7% oxygen.
The take home message is, DO NOT carry liquid nitrogen tanks in the cab of the vehicle. Securely fasten the tank in the box of the pickup and clip down the lid with a zip tie or clip to prevent the lid from opening and the plug flying out. If working within an area with bulk or transporting liquid nitrogen tanks, proper ventilation is critical. If a person experiences sleepiness, dizziness, nausea, or vomiting, these are warning signs of nitrogen inhalation.
Frozen Plugs in Liquid Nitrogen Tanks
Even with the lid and plug in the semen tank, nitrogen gas is being released, which is important, because tanks also need to vent liquid nitrogen. If the plug/stopper becomes frozen in the neck, this prevents the gas from escaping, causing pressure to build up and potentially explode. This is a dangerous situation. If a plug becomes frozen in the neck. Take a drill and bit and use it to create a hole in the styrofoam to allow ventilation. Use a screw drive to chip away the frozen styrofoam without destroying the neck of the tank.
Safety comes first when working around liquid nitrogen, from bulk tanks to tanks that transport semen. Encourage family and employees to watch safety videos, and if they are feeling symptoms of nitrogen exposure, go to fresh air and notify the appropriate individuals. Ventilation is critical.
For information contact Robin Salverson, SDSU Extension Cow Calf Field Specialist at 605-374-4177, or any member of the SDSU Extension Beef Team.
