About anhydrous ammonia
Q1: What is anhydrous ammonia?
Anhydrous ammonia is the gas form of ammonia that contains no water. It is a corrosive gas or colorless liquid, stored and used as a refrigerant under pressure in equipment that is specifically designed to handle the pressure and chemical properties of ammonia. It is flammable at high concentrations. Anhydrous ammonia is commonly used as a refrigerant for cooling and freezing large areas, such as a skating rink or an ice tank.
Q2: What are the human health impacts of anhydrous ammonia?
The potential human health effects of ammonia vary depending on concentration. For example, in smaller concentrations, it could be an unpleasant odor that is typically associated with smelling salts. However, at concentrations greater than 300 parts per million, ammonia may be dangerous to life and health and its effects may be irreversible. Direct exposure to anhydrous ammonia may result in chemical burns or frostbite injuries. if someone is exposed to anhydrous ammonia, they should seek medical attention immediately.
Safe use of anhydrous ammonia at the NRC
Q3: What does the NRC use anhydrous ammonia for?
The NRC's Ocean, Coastal and River Engineering Research Centre lab in St. John's, Newfoundland and Labrador, uses anhydrous ammonia as a refrigerant to create ice conditions in our ice tank. Our ice tank is used to test how ships manage varying thicknesses and strengths of ice using scale model vessels.
Q4: How much anhydrous ammonia is used at the NRC facility in St. John's?
The St. John's facility uses up to 9,000 kg (9 tonnes) of anhydrous ammonia in the refrigeration plant.
Q5: Do other NRC facilities use anhydrous ammonia?
The St. John's facility is the only NRC facility that uses a significant amount of anhydrous ammonia.
Q6: How long hasanhydrous ammoniabeen used at the NRC's St. John facility?
Anhydrous ammonia has been used at the St. John's facility since the facility opened in 1985.
Q7: Does the NRC have an emergency incident action plan in place to respond to ananhydrous ammonia emergency?
Yes. The health and safety of employees and the local community is a top priority for the NRC and we adhere to municipal, provincial and federal government regulations in all aspects of our operations. The NRC has stringent procedures in place, including for managing emergencies, to ensure hazardous materials like anhydrous ammonia are managed appropriately and monitored closely. Examples of safety systems in place include an emergency notification system and monitoring of ammonia levels in the plant and in other strategic locations. All refrigeration plant operators are licensed by the Province of Newfoundland and Labrador to operate a refrigeration plant.
Anhydrous ammonia is included in the list of hazardous substances under the Environmental Emergency Regulations, 2019. Any facility using more than 4,500 kg (4.5 tonnes) is required to have an environmental emergency plan in place. The St. John's plant uses up to 9,000 kg of anhydrous ammonia.
Q8: What emergency measures are in place in case of an anhydrous ammonia emergency?
In accordance with the Environmental Emergency Regulations, the NRC and local authorities would immediately begin implementing the incident action plan. The specific steps taken and the techniques and procedures used would be incident-specific and could include repairing or plugging leaks and using water-fogging equipment to spray a fine mist of water that converts the airborne ammonia gas to a liquid, which reduces or eliminates the off-site effects.
The NRC has also developed and implemented proactive communication measures to inform members of the public in case of an anhydrous ammonia leak. These measures include working with law enforcement and safety officials, local media and any surrounding businesses that could be impacted by a potential leak.
Although the chances of an emergency incident involving anhydrous ammonia at the NRC are low, the facility has several systems in place aimed at reducing or eliminating the risk of an emergency. Systems have been designed, constructed and are operated in compliance with all federal, provincial and local regulations, codes and best practices. As a result, the presence of anhydrous ammonia in the St. John's facility does not represent an undue risk to surrounding residents.
Q9: How will I know if a dangerous situation results from an anhydrous ammonia leak?
In the case of a leak, you will be notified via the Alert Ready app for cell phones, media broadcasts, social media posts and, in some cases, door-to-door notification.
Depending on the nature of the emergency, responders may take a variety of measures to protect the public. You may be directed to shelter in place, which is effective at protecting the population at large during chemical emergencies. Evacuation of the area would be done only as a last resort.
Q10: Will a COVID-19 mask protect me in the event of an ammonia leak?
No, these types of masks will not protect you. The gas reacts with the skin, eyes and respiratory airways.
Q11: Has there ever been an ammonia leak at the St. John's plant?
There has never been a substantial ammonia leak that required the building to be evacuated. Ongoing monitoring and a rigorous schedule of inspections and preventive maintenance ensure that any minor leaks, should they occur, are identified and rapidly repaired or contained.
Q12: Can a safer substance be used instead of ammonia?
While there are alternatives to ammonia such as synthetic refrigerants, greater amounts of these refrigerants would be needed and systems would need higher levels of energy to operate. Hydrocarbons such as pentane or gases such as propane or butane could be used. However, these gases are flammable and, under certain circumstance can explode. As a result, compared with the use of ammonia, there is an increased risk to the public given the nature of these gases. Ammonia has a long history as a safe refrigerant. Ammonia poses no undue risk when used in systems that are designed and installed correctly and operated appropriately.
For these reasons, ammonia is the preferred choice. In addition, people can smell ammonia at concentrations of less than 1 part per million (the average person would not notice any substantive health effect until the ammonia concentration is 30 parts per million). At these low concentrations, the effect is temporary and ends when the exposure stops. Detailed information on exposure is available in the Ammonia Chemical Profile available on the Canadian Centre for Occupational Health and Safety's website.
Q13: What are the environmental impacts of an ammonia leak?
Environmental impacts of an ammonia leak would be relatively minor. The gas would lessen over time and join the nitrogen cycle in the environment and eventually fall as precipitation, which would be taken up by plants and move through the ecological cycle like all other nitrogen. Any liquids that may result from water fogging would be collected on site and disposed of appropriately. If liquid did get off site, it would move into the storm sewer system, where it could be recovered downstream of the facility for disposal.