Throughout your career, you may have encountered or used corrosive substances without realising their hazardous chemical properties. This article explores corrosive substances in detail, highlighting the associated risks, the differences between acids and bases, and guidelines for their safe handling and storage.
What is a Corrosive Substance?
Corrosive chemicals are substances that degrade certain materials, such as metal and stone, through complex chemical reactions. According to the Australian Dangerous Goods (ADG) Code, corrosive substances are classified as Class 8 - Corrosive Substances.
The ADG Code defines corrosive substances as:
“Substances which, by chemical action, will cause severe damage when in contact with living tissue, or, in the case of leakage, will materially damage, or even destroy, other goods or the means of transport.”
If corrosive substances leak or spill, they can damage and destroy a wide range of materials. As this definition indicates, corrosive substances harm both living tissue and materials through chemical corrosion.
The Australian Standard AS 1216 - Class Labels for Dangerous Goods outlines the design and selection of labels and pictograms for dangerous goods, including Class 8 corrosive substances. The symbol used for this classification is the Class 8 Corrosive Diamond.
Risks Posed by Corrosive Substances
Corrosive liquids and substances pose significant risks to people, property, and the environment due to their ability to degrade materials such as skin, eye tissue, steel, and stone.
Risks to People
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Skin Contact: Corrosive substances can cause severe burns by dissolving flesh on contact.
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Eye Exposure: Contact with corrosives can result in serious eye damage, including corneal injury or blindness.
Risks to Property
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Structural Damage: Corrosives can corrode vehicles, structures, tools, and equipment when spilled.
Environmental Risks
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Soil and Water Contamination: Corrosive spills can contaminate natural ecosystems, harming wildlife, farm animals, and marine life.
An accidental release of corrosive substances can lead to widespread harm, affecting people, workplaces, and the surrounding environment.
Types of Corrosive Substances
Corrosive substances are broadly divided into two categories: acids and bases.
1. Acids
Acids are substances that:
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Neutralise alkalis
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Turn blue litmus paper red
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Dissolve certain metals
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Have a sour taste
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Exhibit a pH level below 7
Examples of Acids:
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Sulfuric Acid (H₂SO₄)
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Hydrochloric Acid (HCl)
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Nitric Acid (HNO₃)
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Citric Acid (C₆H₈O₇)
2. Bases
Bases are substances that:
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Neutralise acids
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Turn red litmus paper blue
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Taste bitter
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Feel slippery to the touch
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Exhibit a pH level above 7
Examples of Bases:
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Sodium Hydroxide (NaOH)
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Calcium Hydroxide (Ca(OH)₂)
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Sodium Carbonate (Na₂CO₃)
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Aluminium Hydroxide (Al[OH]₃)
Safe Storage of Corrosive Substances
Proper storage is crucial for maintaining safety in workplaces where corrosive substances are present. Key guidelines include:
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Segregation of Acids and Bases
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Store acids and bases separately to prevent neutralisation reactions, which can produce dangerous by-products or generate heat.
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Use of Compliant Storage Units
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Store corrosives in outdoor chemical storage containers or indoor chemical storage cabinets that meet the Australian Standard AS 3780.
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Access to Safety Data Sheets (SDS)
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Keep Safety Data Sheets readily available for reference.
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Clear Safety Signage
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Display relevant safety signage to ensure awareness in areas where corrosives are stored.
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Personal Protective Equipment (PPE)
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Use appropriate PPE, such as corrosion-resistant gloves and eye protection, when handling corrosives.
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Chemical Spill Kits
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Place spill kits near storage areas to manage spills promptly and minimise risks.
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By understanding the properties of corrosive substances and adhering to proper storage and handling procedures, workplaces can mitigate risks and ensure the safety of people, property, and the environment.
