Understanding the Globally Harmonized System: What Chemical Manufacturers Need to Know About GHS Compliance

The globally harmonized system addresses a challenge: the $1.7 trillion annual international trade in chemicals previously operated under multiple conflicting classification and labeling schemes. The Globally Harmonized System of Classification and Labeling of Chemicals (GHS) is an internationally agreed-upon standard managed by the United Nations. Most major countries had enacted it by 2017. Standardizing the GHS labeling system reduces compliance costs and promotes regulatory efficiency.

This piece will explain what the globally harmonized system is, its classification framework, globally harmonized system labels and pictograms, and compliance requirements that chemical manufacturers must meet.

What is the Globally Harmonized System of Classification and Labeling of Chemicals

The United Nations adopted the Globally Harmonized System of Classification and Labeling of Chemicals in 2003, concluding work that began at the 1992 Rio Conference on Environment and Development. The International Labor Organization, the Organization for Economic Co-operation and Development, various governments, and stakeholders agreed to develop a globally coordinated hazard classification and compatible labeling system during this Earth Summit, with a target completion date of 2000.

This initiative responded to a fundamental problem: every major market had developed its own method for classifying and communicating chemical hazards. Workers, consumers, and businesses moving products across borders faced confusion and barriers.

The Globally Harmonized System of Classification and Labeling of Chemicals serves as an internationally agreed-upon standard managed by the United Nations, set up to replace the assortment of hazardous material classification and labeling schemes previously used around the world.

GHS itself is not a law or compulsory provision of any treaty. It provides a common infrastructure for participating countries to use when implementing national hazard classification and communication standards. Most major economies have incorporated GHS principles into their regulations. The European Union's CLP Regulation, OSHA's Hazard Communication Standard in the United States, and WHMIS in Canada are examples.

Core Elements of GHS

The globally coordinated system establishes standardized hazard testing criteria, universal warning pictograms, and safety data sheets that provide users of dangerous goods with consistent organization of relevant information.

GHS developed two major standardized elements: rules for classifying the hazards of chemical products (substances, materials, or mixtures) and hazard communication tools. These communication tools have the format for safety data sheets, content for labels and SDSs with hazard and precautionary statements, symbols, and signal words.

The system defines criteria for classification of health, physical, and environmental hazards. A given product often fits in more than one hazard class under these classification criteria. To name just one example, a typical solvent may fit in at least three classes: flammable liquid, skin irritant, and narcotic effects causing drowsiness or dizziness.

Most hazard classes are divided into categories based on the hazard's severity. A particular toxic material may be classified as either fatal if inhaled, toxic if inhaled, or harmful if inhaled. The concentration and exposure parameters determine this.

How GHS Is Different from Previous Classification Systems

Many different regulations on hazard classification existed in different countries before GHS was created and implemented, resulting in multiple standards, classifications, and labels for the same hazard. A chemical classified as flammable in one country might be assigned a different hazard category, or no hazard at all, in another jurisdiction. Safety labels varied, and Safety Data Sheets followed different structures depending on location.

The transition from previous systems to GHS brought structural changes that mattered. The old system used 7 orange and black hazard symbols, whereas GHS introduced 9 hazard pictograms displayed as red and black diamonds. Substances are now categorized into hazard classes and hazard categories instead of being assigned to one of 15 categories of danger. The new framework has 16 physical hazard classes, 10 health hazard classes, and 2 environmental hazard classes.

Signal words represent another key difference. GHS uses only two signal words — Danger and Warning — on chemical labels to give a quick indication of hazard severity level. These replace the previous indication of danger words such as corrosive, harmful, irritant, and flammable.

The old Risk and Safety phrases (R and S phrases) have been replaced by Hazard and Precautionary Statements. Hazard statements are separated into H200s for physical hazards, H300s for health hazards, and H400s for environmental hazards. Precautionary statements are organized into P100s for general guidance, P200s for prevention, P300s for response, P400s for storage, and P500s for disposal.

Benefits of GHS Implementation for Chemical Manufacturers

The globally coordinated system improves protection of human health and the environment by providing a system for hazard communication that people can understand internationally. GHS promotes uniform treatment of chemicals across countries and aids sound management of chemicals around the world.

Chemical manufacturers gain practical advantages. Companies only have to classify once rather than navigating multiple inconsistent classification and labeling schemes. This reduces the cost of complying with different systems in various markets. Signal words, pictograms, and hazard statements now have the same meaning across all settings and sectors. Better hazard communication reduces risk through improved understanding and produces simpler and more consistent product labels.

Trade facilitation emerges as a benefit that matters. GHS allows for easier export of chemical products to foreign markets by eliminating country-specific documentation and testing standards. Consistent labels reduce logistical complexities and create a more efficient and secure chemical supply chain. The system encourages safe transport, handling, and use of chemicals while promoting better emergency response to chemical incidents.

GHS Hazard Classification Framework

Hazard classification under the globally harmonized system works through a framework that organizes chemical dangers into classes and categories. GHS organizes the hazard characteristics of chemicals based on hazard classes, which represent physical, health, or environmental effects such as flammability or acute toxicity. These are subdivided into numerical hazard categories based on the severity of the hazard.

Manufacturers get clear criteria for determining how to classify and communicate the risks associated with their chemical products through this approach.

Physical Hazard Classes

Physical hazards are based on a product's physical or chemical properties, such as flammability, reactivity, or corrosivity to metals. The global harmonized system defines 17 physical hazard classes.

These have explosives (with categories from unstable explosives through divisions 1.1 to 1.6), flammable gasses, aerosols, oxidizing gasses, and gasses under pressure. Flammable liquids are divided into four categories. Category 1 represents the most severe hazard. Flammable solids fall into two categories.

Additional physical hazard classes address reactive properties. Self-reactive substances and mixtures, along with organic peroxides, are classified into types A through G. Pyrophoric liquids and pyrophoric solids each have a single category for substances that catch fire when exposed to air. Self-heating substances possess two categories, while substances that emit flammable gasses when in contact with water are divided into three categories.

The framework also has oxidizing liquids and oxidizing solids (each with three categories), corrosive to metals (one category), and desensitized explosives.

Health Hazard Classes

Health hazards are based on knowing how a product causes a health effect, such as eye irritation, respiratory sensitization, or carcinogenicity. The globally harmonized system establishes 10 health hazard classes.

Acute toxicity, which covers oral, dermal, and inhalation routes, spans five categories. Categories 1 and 2 are fatal and Category 4 is harmful. Skin corrosion and irritation divides into Categories 1A, 1B, 1C, and 2. Serious eye damage and eye irritation has Categories 1, 2A, and 2B.

Respiratory and skin sensitization are classified into Categories 1A and 1B. Germ cell mutagenicity, carcinogenicity, and reproductive toxicity each use Categories 1A, 1B, and 2. Category 1A represents known human hazards and Category 1B indicates presumed human hazards based on animal studies.

Target organ toxicity following single exposure and repeated exposure both employ Categories 1 and 2. Aspiration hazard, which addresses the risk of liquid chemicals entering the airways, has a single category.

Environmental Hazard Classes

Environmental hazards comprise two classes under the globally harmonized system. The first addresses hazards to the aquatic environment, divided into short-term (acute) and long-term (chronic) aquatic toxicity.

Acute aquatic toxicity means the intrinsic property of a substance to be injurious to an organism in a short-term aquatic exposure. Acute categories range from 1 to 3. Category 1 carries the hazard statement "Very toxic to aquatic life" and requires a warning signal word.

Chronic aquatic toxicity addresses adverse effects during exposures determined in relation to the organism's life cycle. Chronic categories extend from 1 to 4, with Category 4 based on persistence alone in the absence of toxicity data.

The second environmental hazard class covers substances hazardous to the ozone layer, chemicals regulated under the Montreal Protocol on Substances that Deplete the Ozone Layer. Methyl bromide is the only pesticide listed in this category currently.

Classification of Chemical Mixtures

Classifying chemical mixtures requires methodologies beyond single-substance evaluation. The globally harmonized system contains conservative bridging principles for classifying untested chemical mixtures.

Classification relies on additivity for many hazard classes, where concentrations of all ingredients classified for a particular hazard contribute to the mixture's overall classification. M-factors are established to give increased weight to substances classified as Aquatic Acute 1 or Aquatic Chronic 1 when classifying mixtures for aquatic environmental hazards.

Generic concentration limits apply to most health hazards, while concentration limits set for substances listed in regulatory annexes take precedence.

Understanding Globally Harmonized System Labels and Pictograms

GHS labels serve as the main communication tool between chemical manufacturers and end users. They convey hazard information at the point of use. OSHA's 29 CFR 1910.1200 Hazard Communication Standard requires these labels to contain six elements.

Required Label Elements

Every shipped container requires specific information. The product identifier lists the chemical name, code number and batch number. Workers can cross-reference safety information between the label and Safety Data Sheet with this identifier. This identifier must match across both documents.

Supplier information has the manufacturer's or importer's name, address and telephone number. Workers and safety managers need quick access to contact the supplier to clarify or get emergency information.

Platforms like HazLabel automate the extraction of these required elements when chemical manufacturers process Safety Data Sheets and generate compliant labels. The system verifies them against UN GHS Revision 11 standards. This automation reduces manual errors and keeps product lines consistent.

Globally Harmonized System Pictograms and Their Meanings

Pictograms consist of a black hazard symbol on a white background framed within a red border. The globally harmonized system defines nine pictograms. OSHA mandates only eight to use in the United States. Each pictogram may appear only once on a label, even when multiple hazards require the same symbol.

The nine globally harmonized system pictograms represent distinct hazards:

• Health Hazard: Carcinogenicity, reproductive toxicity, respiratory sensitization and chronic health effects
• Flame: Flammable gasses, aerosols, liquids, solids, self-reactive substances and organic peroxides
• Exclamation Mark: Skin and eye irritation, skin sensitization, acute toxicity (harmful) and narcotic effects
• Gas Cylinder: Gasses under pressure that are compressed, liquefied and dissolved
• Corrosion: Severe skin burns, eye damage and substances corrosive to metals
• Exploding Bomb: Explosives, self-reactive substances and organic peroxides
• Flame Over Circle: Oxidizing gasses, liquids and solids that intensify fires
• Skull and Crossbones: Acute toxicity that may be fatal or toxic through ingestion or skin contact
• Environment: Aquatic environmental toxicity (not mandatory under OSHA HCS)

Signal Words: Danger vs Warning

Signal words indicate hazard severity at a glance. The globally harmonized system uses only two signal words: Danger and Warning.

Danger applies to the most severe hazard categories. Warning addresses less severe hazards. Only one signal word appears on the label when a chemical presents multiple hazards. That word is Danger if any hazard requires it, taking precedence over Warning. The signal word must match the classification listed in the SDS.

Hazard and Precautionary Statements

Hazard statements describe the nature and degree of risks using standardized phrases. A compound causing kidney damage reads: "Causes damage to kidneys through prolonged or repeated exposure when absorbed through the skin". These statements remain consistent whatever the manufacturer or substance. H-codes identify them, starting with H2 for physical hazards, H3 for health hazards and H4 for environmental hazards.

Precautionary statements provide recommended actions addressing prevention, response, storage and disposal. Workers need clear guidance at the time they handle chemicals. An example reads: "Do not breathe dust/fume/gas/mist/vapors/spray. Get medical advice/attention if you feel unwell. Dispose of contents/container in accordance with local/regional/national and international regulations". These statements use P-codes. The first digit indicates the category: P1 for general, P2 for prevention, P3 for response, P4 for storage and P5 for disposal.

Safety Data Sheet Requirements Under GHS

Chemical manufacturers must provide Safety Data Sheets for each hazardous chemical to downstream users to communicate information on these hazards. OSHA revised the Hazard Communication Standard in 2012 to line up with the globally harmonized system and transition from Material Safety Data Sheets (MSDS) to Safety Data Sheets (SDS) with a standardized structure.

16-Section SDS Format

The SDS contains the same information as the MSDS, except SDSs are now required to be presented in a consistent user-friendly, 16-section format. This standardization will give consistency across international borders and facilitate safer chemical management throughout supply chains.

Sections 1 through 8 contain general information that is vital for immediate decision-making about chemical handling, storage and emergency response. The chemical on the SDS gets identified in Section 1, along with the recommended uses and essential contact information of the supplier. Section 2 identifies the chemical's hazards and appropriate warning information. This includes hazard classification, signal words, hazard statements, pictograms and precautionary statements. Ingredients contained in the product get identified in Section 3, which covers impurities and stabilizing additives.

Sections 4 through 8 cover first-aid measures, fire-fighting measures, accidental release measures, handling and storage, and exposure controls.

Technical information appears in Sections 9 through 11. Physical and chemical properties associated with the substance or mixture get identified in Section 9. Section 10 describes the reactivity hazards and chemical stability information. Toxicological and health effects information appears in Section 11.

Sections 12 through 15 are non-mandatory under OSHA regulations since other agencies regulate this information. Section 12 provides information to review environmental impact. Section 13 addresses disposal considerations, Section 14 covers transport information, and Section 15 identifies safety, health and environmental regulations specific for the product.

When the SDS was prepared or when the last known revision was made gets indicated in Section 16.

Platforms like HazLabel streamline SDS management by automating the parsing of these 16 sections and extracting critical information for label generation. This will give consistency between SDS documentation and product labels.

Key Differences Between MSDS and SDS

Material Safety Data Sheets followed a variable format with simple sections that could differ between chemical manufacturers. All SDSs follow the GHS's standard sixteen-section format, whereas MSDS formats can vary between organizations. The transition from MSDS to SDS represents a substantial advancement in global hazard communication standards. SDS offers a more standardized and complete 16-section format.

The hazard classification system evolved substantially. MSDS focused on physical hazards and health hazards, while SDS maintains these categories and adds environmental hazards. Documentation requirements have become more structured under SDS requirements and follow strict GHS guidelines.

Information Required in Each SDS Section

Each section contains specific mandatory information. Section 1 requires the product identifier used on the label, manufacturer contact details and recommended use with any restrictions. Section 2 must include the hazard classification, signal word, hazard statements, pictograms and precautionary statements. It also needs a description of any hazards not otherwise classified.

Section 3 requires chemical name, common name and synonyms, CAS number and other unique identifiers. For mixtures, the chemical name and concentration of all ingredients classified as health hazards must be included. Exposure limits, engineering controls and personal protective measures to minimize worker exposure get indicated in Section 8.

GHS Compliance Requirements for Chemical Manufacturers

Chemical manufacturers and importers bear specific obligations under OSHA's revised Hazard Communication Standard. They must classify, label and communicate chemical hazards properly.

Product Classification Obligations

Chemical manufacturers, importers and distributors must identify and classify chemical hazards before they develop labels. Appendix A contains classification criteria for health hazards. Physical hazards appear in Appendix B of the revised Hazard Communication Standard. Manufacturers must think about the full range of available scientific data when they classify chemicals.

After classification, manufacturers and importers must get or develop an SDS for every hazardous chemical or mixture they produce or import.

Labeling and Packaging Standards

The HCS requires chemical manufacturers, importers or distributors to label each container of hazardous chemicals leaving the workplace. Each container must be labeled, tagged or marked with product identifier, signal word, hazard statements, precautionary statements, pictograms and supplier contact information.

Employers must keep these labels on containers. Tanks, totes and drums all need proper labeling. Labels must remain legible. Information such as hazards and directions for use cannot get defaced, fade or wash off. Employers must relabel items if labels are removed or defaced. Portable containers intended for immediate use by the employee who performs the transfer need no labels.

Platforms like HazLabel automate label generation from SDS data and verify all required elements against UN GHS Revision 11 standards.

Record Keeping and Documentation

Employee exposure records must be kept for 30 years. Employers must keep a list of substances and mixtures in use each year, along with corresponding SDS files. These documents show where and when substances were used.

Training Requirements for Employees

Employers must train all workers to read and understand GHS-compliant labels and Safety Data Sheets. Training must occur before the original work assignment and whenever new hazards are introduced.

GHS Implementation by Region and Country

Regional adoption of the globally coordinated system varies substantially across major economies, with each jurisdiction implementing GHS through distinct regulatory frameworks and timelines.

United States OSHA HCS 2012 Standards

OSHA published the Hazard Communication Standard (HCS-2012) based on the 3rd revised edition of the UN GHS. The standard required compliant labels and SDSs for hazardous chemicals starting June 1, 2015. OSHA amended the HCS on May 20, 2024, to arrange it with the 7th revised edition of the UN GHS and select provisions from the 8th revised edition. The regulation took effect on July 19, 2024.

Manufacturers, importers and distributors must comply with modified provisions for substances by January 19, 2026, and mixtures by July 19, 2027.

European Union CLP Regulation

The EU published the Classification, Labeling and Packaging of Substances and Mixtures (CLP Regulation) on January 20, 2009. The regulation replaced the Dangerous Substances Directive and Dangerous Preparations Directive in phases. Chemical substances required mandatory application since December 1, 2010, and mixtures were enforced since June 1, 2015.

Canada WHMIS 2015

The Government of Canada published the Hazardous Products Regulations on February 11, 2015, modifying WHMIS to incorporate the UN GHS for workplace chemicals. Health Canada published an amendment on January 4, 2023, arranging it with the 7th revised edition of the UN GHS and adopting parts of the 8th revised edition. The amendment entered into force on December 15, 2022, with a 3-year transition period.

Timeline and Transition Periods

Canada grants suppliers a transition period to December 15, 2025, to bring product classifications, safety data sheets and labels into compliance. Platforms like HazLabel help manufacturers manage these regional differences by automating label generation that complies with specific jurisdictional requirements.

Conclusion

The globally aligned system represents one of the most important advances in workplace safety and international trade for the chemical industry. We covered the detailed framework chemical manufacturers must understand, from hazard classification in physical and health categories to the standardized labels with pictograms and signal words that ensure consistent communication.

The 16-section SDS format provides structured hazard information. Regional compliance requirements need careful attention to jurisdiction-specific timelines.

Platforms like HazLabel streamline this complex process. They automate SDS parsing and label generation verified against UN GHS standards. Proper GHS implementation protects workers and reduces regulatory burden. It aids smoother global commerce in chemicals.