 Commonwealth of Australia 2010

76.2Hazard communication

76.2.1Labelling and hazard warning systems

In Australia, hazardous substances must be sold in containers that are appropriately labelled. Appropriate labelling communicates to users information on the appropriate use and disposal of the chemical, thus minimising risks to the environment from improper practices. All states and territories have adopted a uniform system for labelling which seeks to ensure that appropriate information about the hazardous substance is conveyed to the user via standardised phrases and symbols.

Under the ADG Code, sodium cyanide is assigned a dangerous goods class of 6.1, with United Nations (UN) numbers of 1935 (“cyanide solution N.O.S.” [30% alkaline solution] – HAZCHEM 2X, HIN 66/60) and 1689 (solid – HAZCHEM 2X, HIN 66). The number in the HAZCHEM code (Hazchem Emergency Action code) refers to firefighting extinguishing media, and the 2 denotes ‘fine water spray’. The following letter denotes the nature of hazards presented by the substance - X indicates no risk of violent reaction or explosion; recommended personal protective equipment is liquid-tight chemical protective clothing and breathing apparatus; and appropriate measures are to contain, and that spillages and decontamination runoff should be prevented from entering drains and watercourses. The HIN (Hazard Identification Number) of 66 indicates ‘highly toxic substance’ and 60 indicates ‘toxic or slightly toxic substance’ (Appendix C in NTC, 2007).

Classification under the OECD Globally Harmonised System for Classification and Labelling of Chemicals (GHS; UNECE, 2005) is indicated in Appendix 3.

Guidance is also available to accompany the National code of practice for the storage and handling of dangerous goods (NOHSC, 1990).

76.2.2Material safety data sheets (MSDS)

77.Revised MSDS code

The National code of practice for the preparation of material safety data sheets, 2nd edition, published by the National Occupational Health and Safety Commission (NOHSC, 2003), provides minimum requirements for information in SDSs to ensure their relevance and applicability to occupational, public and environmental safety. The revision of the MSDS Code addressed various technical elements and facilitates Australia remaining consistent with international approaches to hazard communication, i.e. with the Globally Harmonised System for the Classification and Labelling of Chemicals (GHS). The major focus of the revised MSDS Code is to incorporate the GHS information provisions of the National standard for the storage and handling of workplace dangerous goods [NOHSC:1015(2001)]. The revised MSDS Code came into effect on 24 April 2006.

Provision of ecological information (so far focussing on aquatic toxicity) is a requirement of the GHS, under Section 12 of the 16 header MSDS format that will become the international standard. The availability of information on ecotoxicity, persistence, degradability and mobility in the SDS is intended to assist the evaluation of the environmental impact of the material if it is released to the environment. It can assist in handling spills, and evaluating waste treatment practices. At the time of publication of the revised MSDS Code, there was no consistent national requirement under the Commonwealth, state and territory hazardous substances regulations to provide this aquatic ecotoxicity information. However, under Dangerous Goods regulation, some states and territories have required this information.

78.MSDS for sodium cyanide

In general, most of the MSDSs comply with the national code of practice concerning the consideration of accidental environmental release (spill response) measures. With respect to spill response, treatment and disposal, most of the MSDSs available emphasise the following key requirements:

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  Immediate action, Communication, and Evacuation/Access Restriction;
  
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  Trained spill response personnel and Personal Protective Equipment;
  
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  Spill Source Control and Containment;
  
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  Cleanup Procedures and Neutralisation/Detoxification; and
  
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  Disposal/Recycling.
  

At least one MSDS recommended using hydrogen peroxide to detoxify cyanide at spill situations; however, this is a strong oxidizer that may cause a violent reaction and should be avoided due to the potential for generation of HCN gas at the spill site.

One MSDS indicates that for small spills involving cyanide solutions, following adsorption of spilled material and removal of the cyanide-containing absorbent material, the spill area should be flushed away using water containing some alkaline material such as sodium carbonate. However, treated wastes should be contained, collected and disposed of appropriately. An alternative method involves adsorption of spilled material, followed by excavation and removal of a conservative amount of contaminated surface soil for treatment. The spill area and collected contaminated soil may be neutralized with an excess amount of dilute sodium hypochlorite or calcium hypochlorite.

Spills of sodium cyanide into natural waters are particularly difficult to remediate without further damaging the water body by, for example, adding oxidising agents. For such spills, an appropriate action may be to allow natural degradation, coupled with dilution and dispersal, to take its course. Preservation of sensitive fauna may be possible by their collection and relocation, while netting and fencing may be used to prevent their entry to contaminated ponds. Pumping of contaminated water from natural waters into tankers for off-site treatment or holding ponds may also be possible to avert degradation of the environment. Remedial actions may potentially include blocking stream flow while in-situ treatment or pumping of contaminated water to tanks or containment areas, such as lined ponds. The choice of remediation option following spill incidents depends on public and worker safety, environmental, social and practical considerations.

Limited advice is provided in MSDS on spill incident management of sodium cyanide whether the incident occurs during rainfall or unfavourable weather conditions, or when associated with a fire and fire emergency services are required to extinguish the fire using water or other substances.

It is likely that these MSDSs will have been revised to address the revised MSDS Code. When such revisions occur it would be appropriate to ensure that advice provided which relates to the environment (spillage management, and ecological information if it is included) is consistent and correct.