What are hazardous chemicals?
Exposure to a hazardous chemical (sometimes called a hazardous substance) can cause pain, injury, serious illness or death.
Hazardous chemicals can be solid, liquid or a vapour and enter the body by being inhaled into the lungs, absorbed through the skin or ingested through the mouth. The effect of a hazardous chemical will depend on its toxicity and the extent and duration of the exposure.
An obvious hazardous chemical is a poison such as cyanide. Other examples include acids and alkalis, which are corrosive, causing burns or skin and eye irritation. Exposure to solvents or explosive fumes may cause dizziness and nausea. Some hazardous chemicals may cause cancer, while others such as mercury and lead can build up concentrations in the body over time with very harmful effects.
A substance is deemed to be a hazardous substance if it meets the classification criteria specified in the Approved Criteria for Classifying Hazardous Substances [NOHSC:1008(2004)] available from Safe Work Australia.
Substances classified as a hazardous substances according to the approved criteria are listed in the online Hazardous Substances Information System hosted by Safe Work Australia.
Are hazardous chemicals the same as dangerous goods?
Many hazardous chemicals are also classed as dangerous goods.
Dangerous goods are chemicals, substances, mixtures or articles that, because of their physical, chemical (physicochemical) or acute toxicity properties, present an immediate hazard to people, property or the environment. The types of substances classified as dangerous goods include explosives, flammable liquids and gases, corrosives, chemically reactive or acutely (highly) toxic substances.
Large quantities of various dangerous goods are commonly used on mine sites. They may be identified by dangerous goods placards, which are attached to tanks, large containers and gas cylinders.
Hazardous chemicals and dangerous goods used at mining operations in Western Australia are regulated by the Resources Safety Division of the Department of Mines and Petroleum.
Go to the dangerous goods landing page for information on the use, storage, handling, transport and disposal of explosives and other dangerous goods.
Some sites use chemicals that are associated with national security concerns and may require vigilance. What are chemicals of security concern?
Where are hazardous chemicals found on mining operations?
Process plants and refineries
A wide range of hazardous chemicals is typically found in process plants and refineries.
The more common ones are:
- acids such as sulphuric acid, hydrochloric acid and nitric acid, which are frequently used to dissolve metals in ores
- caustic soda (sodium hydroxide), which can be used as a reagent to dissolve bauxite in alumina refineries, or to neutralise acid process streams and wastes
- sodium cyanide, which is used on most gold mines to help process the ore
Xanthates, used as a flotation chemical, solvents and compressed gases may also be found. Hazardous chemicals such as sulphur dioxide, hydrogen sulphide, carbon monoxide and oxides of nitrogen may be generated during the processing of mineral ores.
Sodium cyanide is strictly managed to minimise worker exposure through direct contact or from hydrogen cyanide gas.
Mine site laboratories commonly have the greatest variety of chemicals found on the mining operation, though typically in relatively small quantities. Acids used to digest materials generally represent the greatest risk, although all chemicals must be handled carefully.
Fire assay laboratories can use lead reagents, while the sample preparation area may need to manage crystalline silica dust, fibres generated while preparing samples, and volatile fumes.
For security reasons, few people have access to gold rooms, but common hazardous chemicals found there are acids, cyanide and fluxes. Ammonia from electrowinning and lead, arsenic or mercury from smelting gravity gold may also need to be managed.
Mine site workshops typically include light and heavy vehicle, mechanical and electrical areas. Most oils, greases and other lubricants present a low hazard. However, cleaning solvents, spray painting chemicals and dusts generated during grinding and sand blasting need to be controlled.
Fumes generated from welding, cutting or vehicle exhausts can be a potential issue, particularly in enclosed areas.
Water treatment plants
Many mines have reverse osmosis or other water treatment plants. Hazardous chemicals that need to be managed to minimise exposure include acids and chlorine.
Hazardous materials that are mined or produced during mining
One of the most common dusts encountered on mine sites is quartz (crystalline silica), which is a mineral found in many orebodies.
Several varieties of asbestiform minerals may be encountered during exploration and mining of iron ore, base metals and gold.
Diesel emissions from equipment contain a number of toxic chemicals.
Management of hazardous chemicals
Safety data sheets (SDSs)
A safety data sheet (SDS), previously called a material safety data sheet (MSDS), is a document that provides information on the properties of hazardous chemicals and how they affect health and safety in the workplace.
In an SDS, information on the chemical hazards is based on the Globally Harmonized System (GHS) of classification, rather than the hazardous substances and dangerous goods classifications. Both provide equivalent levels of information on chemical hazards and health and safety precautions, and either may be used in the workplace to meet the requirements for managing risks under the Mines Safety and Inspection Regulations 1995.
More information can be found in Safe Work Australia’s Code of Practice for the Preparation of Safety Data Sheets for Hazardous Chemicals.
General duty of care
Employers have a general duty of care to provide and maintain a working environment in which workers are not exposed to hazards, as far as is practicable.
A risk assessment should be undertaken to determine what hazardous chemicals are allowed on site, and the consequences of exposure that may impact on the health of workers. Along with the risk assessment, the employer needs to establish and maintain a hazardous chemical monitoring system and, where required, a health surveillance program for workers.
Workers and safety and health representatives, where they exist, must be consulted on safety and health matters, which includes developing health surveillance programs.
Safe work practices
Part of the risk assessment before introducing a hazardous chemical to a workplace is to consider the following questions.
- Is the substance is absolutely required for the purpose?
- Is there is a safer alternative?
- How can the chemical and its waste be disposed of with no harmful effects?
- What quantity is required to be kept and how can it be stored safely?
- Is a licence or permit is required and are any legislated safety requirements for the substance (e.g. hydrofluoric acid, mercury)?
It is important to consider that some hazardous chemicals or substances may be generated by work activities (e.g. silica dust, fibres, welding fumes, diesel exhaust).
Most of the information on safe handling and use of hazardous chemicals is available on the SRS or MSDS provided by the supplier of the chemical. This information will include required control measures, such as:
- local exhaust ventilation, ventilation ducting or need for fume cupboards
- suitable personal protective equipment (PPE), such as eye protection, respiratory protection and protective clothing
- the first aid procedures in case of exposure to the chemical.
Maintain a hazardous substances register including the SDSs for all hazardous chemicals on site. The register should be accessible to those who may require it.
People should be aware of the location of the nearest safety shower or eyewash in case of an emergency. Occupational hygiene monitoring may be required to measure workers’ exposure to a contaminant.
More information on management of hazardous chemicals on mine sites is available in Hazardous substances pamphlet below.
Below is a external link that you may find useful.
The National Model Regulations for the control of Workplace Hazardous Substances is available from Work Safe Australia.