This information is to assist in recognising symptoms of cyanide poisoning, and for the provision of timely and appropriate first aid and medical support. It applies to the transport, transfer, storage and use of cyanide on a mine site.
Health effects: Hydrogen cyanide (HCN) is a highly toxic and fast acting gas that is released from sodium cyanide solutions used in gold processing. At higher concentrations it may cause death rapidly. Debilitating, yet milder, symptoms may occur at much lower concentrations (10 - 30ppm). The regulated workplace exposure standard is currently a peak limitation of 10ppm (Safe Work Australia, April 2020 (Guide for preventing and responding to cyanide poisoning in the workplace). Cyanide gas concentrations above 50ppm are considered to be immediately dangerous to life and health (IDLH) (Centre for Disease Control, 1994. Hydrogen cyanide. Immediately Dangerous to Life or Health).
Early signs and mild symptoms may occur within minutes of exposure to HCN that include:
- headache
- dizziness
- feeling faint
- weakness
- fatigue
- shortness of breath
- rapid heart rate
- nausea and vomiting.
Generally, milder symptoms resolve after cessation of exposure without any permanent damage. Symptoms may be delayed if there is skin contact with cyanide gas or solution, as cyanide uptake from skin absorption occurs at a slower rate than inhalation. Also, skin or mucosal contact with cyanide solutions can cause itching, discolouration and corrosion due to the alkalinity.
Inhalation of high concentrations of HCN gas or ingestion of cyanide salts or solutions may lead to low blood pressure, rapid collapse and loss of consciousness, convulsions, cardiac arrest and death.
Emergency response planning
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Key elements of a comprehensive emergency response plan to manage any suspected or actual cyanide poisoning on site, include:
- Medical advisers require current and relevant skills and knowledge, and communicate with the Poisons Information Centre / Toxicologist on 13 11 26, as required.
- Medical centres should have capacity to provide immediate expert advice for the management and treatment of anyone affected by cyanide, including casualties requiring medical evacuation.
- Clear processes for immediate access to that medical advice for the first responders on-site (First Aid/Medics/Nurses) after initial first aid through to ongoing medical supportive management on-site, and medical evacuation as required.
- Clear processes for ensuring prompt availability of the antidote Cyanokit® (Hydroxocobalamin), i.e. on site and accompanying the casualty; and/or available at the medical centre.
- Clear processes for administration of Cyanokit® under the direction of medical advice (if required).
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- All workers (including supervisors and senior management) who work with or in the vicinity of cyanide.
- First responders (first aiders, medics, nurses) require higher level training to be competent in cyanide rescue and immediate management of anyone affected by cyanide.
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- The processes must provide prompt first aid and medical attention.
- If a contractor employee is involved in a cyanide incident, the relevant PCBU(s) must be contacted as soon as possible.
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- A cyanide emergency kit must be readily available and include:
- A copy of the first aid procedures and emergency contact numbers
- A copy of the current Safety Data Sheet (SDS) for the cyanide compound involved, and emergency response plans. Ensure it is replaced if given to medical staff treating the affected worker.
- Portable oxygen cylinder with high flow regulator (15 L/min capacity)
- Non-rebreather mask (adult sizes) with tubing to connect to oxygen regulator, to ventilate conscious casualties.
- Bag-valve mask (air-viva, oxy-viva) connected to oxygen regulator, to ventilate unconscious casualties.
- Guedel airway (oropharyngeal airway; adult sizes) to insert into the mouth to keep the airway open when ventilating an unconscious casualty.
- Intravenous equipment, including; tourniquet, intravenous (IV) cannulae (at least two) and bung, IV giving sets, skin prep swabs, dressings, adhesive tape, sterile disposable syringes and needles; IV fluid bags (use on medical advice).
- Fluoride heparinised blood sample tubes.
- At least 4 pairs of impervious gloves – double gloving is recommended
- Plastic bags labelled ‘Contaminated with Cyanide’.
- Antidote Cyanokit® (hydroxocobalamin) with instructions – stored and replenished according to the manufacturer’s instructions.
- PPE for rescuers including protective eyewear, clothing, gloves and breathing apparatus (BA/SCBA) for escape and rescue.
- Safety shower, shower screen, robe/blanket to manage modesty of exposed workers during decontamination.
- Eyewash stations.
- “Space” or thermal blankets for treating hypothermia or shock.
- Defibrillator.
- Site casualty/ambulance transport vehicle.
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- Contact Poisons Information Centre / Toxicologist on 131126 or designated emergency medical practitioner (as per agreement with the emergency medical centre) at once.
- Assess the situation.
- Danger, Response, Send for help, Airways, Breathing, Circulation, Defibrillation.
- Immediately remove affected worker from the cyanide area.
- Resuscitate in a well ventilated area.
- If skin or hair contact, decontaminate by removing contaminated clothing and washing for at least 20 minutes under running water.
- If eyes affected, wash immediately with water.
- Administer 100% oxygen, whether conscious or unconscious.
- Do not give mouth-to-mouth resuscitation.
- To protect the rescuer, use air-viva, oxy-viva or one-way mask.
- Contact Medical Practitioner/ Poisons Information Centre /Toxicologist to provide advice and direction for ongoing medical supportive treatment.
If mild symptoms and conscious:
- Continue administration of 100% oxygen until resolution of symptoms.
- Continue observations for at least another hour in the treatment room until the patient is asymptomatic and feels well.
- The individual must be removed from further cyanide work and high risk work for that shift as a minimum. High risk work includes driving and use of machinery.
- Arrange medical assessment as soon as possible (at the nearest medical centre on the same day; or telehealth consultation with the registered medical practitioner (RMP) or other medical practitioner.
- Collect and send a urine sample for thiocyanate analysis on day 2 or 3 post exposure (provide pathology lab form from RMP) to confirm the cyanide exposure as a cause of the symptoms.
- Medical clearance by RMP or a medical practitioner is required prior to returning to cyanide work.
If deteriorating and/or unconscious:
- Continue administration of 100% oxygen, supportive treatment and resuscitation (including intravenous lines, CPR as required)
- Arrange urgent medical evacuation to nearest emergency medical centre accompanied by Cyanokit® (hydroxocobalamin) and nurse/first aider
- Continue monitoring status of the patient.
- Administration of Cyanokit® to be given only under the direction of a medical practitioner/toxicologist
- Once alert and orientated, continue to administer oxygen and continue monitoring for at least 4 hours.
- If possible, analyse a urine sample for thiocyanate 2 or 3 days later to confirm the cyanide exposure as a cause of the symptoms.
- Medical clearance by RMP or a medical practitioner is required prior to returning to cyanide work.
Notes:
- The emergency kits must be checked, maintained and re-stocked regularly.
- The location and number of emergency kits and portable oxygen cylinders must be carefully considered so that they are appropriate for the site.
- The antidote Cyanokit® (hydroxocobalamin) must be checked, re-stocked regularly and be of sufficient quantity on-site, to allow for a supply to accompany any medical evacuation.
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Incidents of workers experiencing adverse health effects from cyanide must be reported to the Regulator. Similarly, incidents where workers are exposed to unsafe concentrations of cyanide, are also reportable if they could have caused serious harm to a person.
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