Regulatory Principles of the Globally Harmonized System (GHS Rev. 10)
The Globally Harmonized System of Classification and Labelling of Chemicals (GHS), maintained by the United Nations, establishes international criteria for classifying chemical substances and mixtures by physical, health, and environmental hazards. In modern quantitative laboratory science, compliance is mandatory under OSHA Hazard Communication Standard (29 CFR 1910.1200) and European CLP Regulation (EC 1272/2008).
The Anatomy of GHS Codes: H-Codes vs. P-Codes
Hazard statements are alphanumeric codes consisting of the letter H followed by three digits:
- H200–H299: Physical Hazards (Explosives, Flammables, Self-Reactives, Pyrophorics, Oxidizers, Corrosive to Metals).
- H300–H399: Health Hazards (Acute Oral/Dermal Toxicity, Skin Corrosion, Eye Damage, Mutagenicity, Carcinogenicity, Reproductive Toxicity, STOT).
- H400–H499: Environmental Hazards (Acute and Chronic Aquatic Toxicity, Ozone Depletion).
Precautionary statements follow the letter P followed by three digits:
- P100 Series: General precautions (keep out of reach of children, read label).
- P200 Series: Prevention measures (wear PPE, avoid open flames, use in well-ventilated areas).
- P300 Series: Response protocols (first aid, eye rinsing, poison center contact).
- P400 Series: Safe storage protocols (keep locked, store in cool, ventilated area).
- P500 Series: Proper hazardous waste disposal procedures.
Frequently Asked Questions: Chemical Safety & Laboratory Compliance
When is a secondary container label legally required in a laboratory?
Under OSHA HazCom 2012, if a prepared solution or chemical is transferred from its manufacturer bottle into a secondary vessel (e.g. Schott bottle, beaker, volumetric flask) and is not used immediately during the work shift by the person who transferred it, a secondary container label with product identifier, signal word, and hazard statements is legally required.
How does concentration cut-off affect diluted acid and base solutions?
Concentrated mineral acids (such as 12 M HCl or 18 M H₂SO₄) are Category 1 Skin Corrosives (H314). However, when diluted below the 3.0% generic concentration threshold, the solution no longer meets the criteria for Category 1 corrosion and is de-escalated to Category 2 Skin Irritation (H315) or non-hazardous status below 1.0%.
What is the difference between DANGER and WARNING signal words?
DANGER is reserved for severe hazard categories (e.g., Fatal if swallowed, Severe skin burns, Carcinogen Category 1). WARNING is assigned to less severe hazard categories (e.g., Harmful if swallowed, Skin irritation, Suspected carcinogen Category 2).