CCOHS: Three workers in Fernie, British Columbia lost their lives due to an ammonia leak at the municipal arena and 95 residents living near the arena were evacuated from their homes for five days. The exact cause of the leak has not yet been determined but this incident highlights the need to understand ammonia and the risks that come with its use in the workplace.
What is ammonia?
Ammonia is a toxic chemical commonly found in refrigerants, cleaning products, and fertilizers. It is naturally found as a gas, but it can be pressurized and stored or transported as liquid. . Exposure to a high concentration of ammonia can be fatal. Ammonia has the following characteristics:
- Colourless with a distinct strong odour. However, repeated exposure reduces your ability to smell the gas. This odour fatigue can occur even if the levels of the gas are high.
- As a gas, it may explode if heated. High concentrations can be a fire and explosion hazard, especially in confined areas.
- Very toxic and can be fatal if inhaled.
- Corrosive to the respiratory tract, and causes severe skin burns and eye damage.
- May cause frost bite.
How workers are exposed
Ammonia is most commonly found on farms, in refrigeration systems and in fertilizers and cleaners. On farms, ammonia gas is generated by compost piles on mushroom farms. Manure pits and any indoor or confined spaces where farm animals are kept can contain ammonia gas. Ice rinks and ice manufacturing plants use liquid ammonia in their refrigeration systems. If this liquefied ammonia leaks, it becomes a gas. In its liquid form, ammonia is often diluted and combined with other chemicals and found in fertilizers and cleaning products.
The risks
The highest risk comes from breathing the gas, which can be fatal. The level of risk depends on the concentration of ammonia and the length of exposure time. In low concentrations, exposure can cause irritation to the eyes, nose, and respiratory system. It can also cause chemical and freezing burns on the skin. At high concentration, ammonia gas can be fatal within a few breaths.
How to reduce the risks
Controlling the risks and hazards in the workplace can reduce the potential for injury or disease. The most effective way to manage the risk of exposure to ammonia is to eliminate the source of exposure. If that's not possible, there are other control measures to use. When choosing control measures, start by asking yourself these questions, listed in order of effectiveness.
- Elimination or substitution
- Can a less hazardous material be used?
- Engineering controls
- Can a process that generates less ammonia be used?
- Can ventilation be improved?
- Can ammonia-producing tasks be enclosed by barriers that prevent gas from leaking into other areas of the workplace?
- Administrative controls
- Can warning signs be posted in the work area?
- Can signs explaining ammonia exposure symptoms be posted?
- Can written safe work procedures be posted?
- Can a 24-hour continuous ammonia monitor be connected to an alarm system?
- Personal protective equipment (PPE)
- Do workers have the required respirators, eye wear, and protective clothing?
- Has personal protective equipment been tested to make sure it is working properly?
If there's an ammonia leak, notify a supervisor immediately. Clear the area, and begin emergency procedures.
Resources:
- Ammonia Storage and Use Risk Advisory, WorksafeBC (English Only)
- Ammonia, WorkSafeBC (English Only)
- Ammonia fact sheet, CCOHS