Dealing with ammonia releases

Ammonia (NH 3 ) is naturally produced in small quantities through the decomposition of organic matter and is commonly used in household cleaning products.

Industrial scale production of ammonia is used in manufacture of fertilisers, explosives and sodium cyanide. It is used as a refrigerant gas, in water supply purification, in nickel refinement and in the manufacture of plastics, textiles, pesticides, dyes and other chemicals.

The widespread use, production, transport and transfer of ammonia means an increased likelihood of exposure to people and the environment when an uncontrolled release occurs.

Health hazards

Ammonia is a pungent, colourless gas which is toxic, corrosive and flammable. On contact with water vapour, ammonia forms visible fumes which are denser than air and will remain at ground level for some time.

The gaseous ammonia interacts immediately upon contact with moisture in the skin, eyes, oral cavity and respiratory tract to form ammonium hydroxide, a strong caustic substance which can cause chemical burns. It causes stinging to the eyes and nose, watering of eyes, the generation of excessive mucus (i.e. nose running) and potentially cell damage. The effects on the eyes, nose and lungs could lead to difficulty with vision and breathing.

Liquid ammonia can create freezing temperatures causing cold burns if in contact with skin. Chemical and cold burns may result in necrosis of impacted body tissue.

Acute exposure to gaseous or liquid ammonia from any source may lead to serious injury or potential fatality.

Workers who might be exposed to ammonia should be provided with information, instruction and training about its hazards, safe use, potential control measures and emergency procedures. Signs, labels or placards may also be required.

Direct exposure - actions required

Following exposure to ammonia, and once the person is brought to a safe place, decontamination is necessary. This requires enough clean water for a sustained period of 20 minutes or more of flushing to minimise serious health effects. medical assistance should be obtained as soon as possible.

To minimise the risks of exposure to ammonia, undertake the relevant checks.

Check 1 – Emergency response

• Do any personnel, including emergency responders, wear contact lenses? If so, an exposure may be absorbed by and caught behind the lenses which can trap the ammonia solution, causing eye damage and reducing the effect of decontamination with water.

• Are personnel wearing encapsulated protective suits?

• Are personnel adequately trained to use the equipment required?

• Are medical personnel competent to provide first aid and treatment for ammonia-related injuries?

• Are eye wash and emergency shower stations adequate? Consider their availability, proximity and water quality. Is the temperature and pressure able to sustain the minimum of 20 minutes of continuous water flushing?

Check 2 – Personal protective equipment (PPE)

• Is the PPE right for working in toxic, caustic and cryogenic conditions? Some standard PPE may react with ammonia.

• Some PPE, such as self-contained breathing apparatus (SCBA), makes verbal communication difficult. Has the means of communication been considered with the type of PPE selected?

• Where emergency responders and workers are required to wear full protective suits, are they adequately trained to use the equipment?

• Refer to the safety data sheet (SDS) for the correct PPE. You may also consider using:

– bicep length chemical gloves

– nomex hood

– a K2 Filter in full face respirator

– vapour excluding fog proof mono goggles

– personal ammonia detector

– chemical break open eye wash.

Check 3 – Medical response

• If you haven’t decontaminated the person sufficiently, could absorbed ammonia be released into the confines of the medical transport? Could ammonia come from burns or from the lungs?

• Do the medical services have sufficient information on ammonia burns or inhalation? The SDS should have the correct information, so ensure a current copy is provided to the emergency services personnel.

Check 4 – A release or potential release

• Are the consequences of closing a valve or activating an isolating device of an ammonia system or process unit well understood?

• Are emergency stops well designed, prominently marked, easily accessible and regularly tested?

• Could there be a source of ignition near the release? If it is not a classified hazardous area, could you get a sufficient concentration to ignite the ammonia? Is it possible to isolate the energy sources?

• During maintenance planning, have measures in controlling and containing the release or effects of ammonia been considered? For example:

– water supply for fire protection and prevention of ammonia vapour clouds moving off site

– mechanical or positive pressure ventilation

– using a tarp to deflect or cover life threatening ammonia aerosol or dense gas cloud to facilitate escape or allow safe execution of emergency actions.