This section describes the highest value-added function of laboratory management for the chemical industry.
Reporting the harmfulness and toxicity of a product based solely on its formulation , without physically producing or testing the product.
1. What is GHS?
GHS (Global Safety Higher Education) is a system developed by the United Nations to classify and communicate the hazards of chemicals worldwide using the same criteria and language. It ensures that the same product is advertised in Turkey, Europe, America, and the Far East with the same pictogram, signal word, and hazard expressions. The system is reviewed every two years; the most current version is the 11th revised edition, published on September 12, 2025. This revision clarified the classification criteria for aerosols and chemicals under pressure, added guidance for methods that do not use animal testing for skin sensitization, introduced a new classification for substances and mixtures harmful through their contribution to global warming , and simplified precautionary statements.
2. Structure of GHS
01
Physical injuries
Explosives, flammable gases, aerosols, oxidizing gases, gases under pressure, flammable liquids and solids, self-reactive substances, pyrophorics, self-heating substances, substances that release flammable gas on contact with water, oxidizing liquids and solids, organic peroxides, corrosives for metals, desensitized explosives.
02
Health risks
Acute toxicity (oral, dermal, respiratory), skin corrosion and irritation, serious eye damage and irritation, respiratory and skin sensitization, germ cell mutagenicity, carcinogenicity, reproductive system toxicity, specific target organ toxicity (single and repeated exposure), aspiration hazard.
03
Environmental damage
Harmful to aquatic life (acute and chronic), harmful to the ozone layer; with the 11th revision, harmful through contribution to global warming.
3. How is a mixture classified?
There are three ways of classification, and they follow a priority order:
PATH 1
The mixture's own test data
If the mixture itself has been tested, the data is used directly. This is the most reliable but also the most expensive and slowest method.
PATH 2
Bridging principles
The mixture has not been tested, but if data on similar mixtures is available: dilution, production batch, concentration, interpolation, essentially similar mixtures, and aerosol guidelines.
ROAD 3
Calculation from components
Deriving the classification of the mixture from the hazard data and concentrations of the components, using defined formulas and threshold values.
In practice, the vast majority of mixtures are classified using a third method . The reason is simple: conducting a complete test set for every new formulation variant is not feasible in terms of both cost and time. Classification rules, by acknowledging this fact, allow for calculations based on compositional information.
4. How does the calculation work?
Each hazard class has its own calculation logic. The main ones are:
Pest class
Computational logic
Required data
Acute toxicity
Calculation of the ATE value of the mixture from acute toxicity estimates of the components using the inverse summation formula.
Component ATE values and concentrations
Skin abrasion/irritation
Additivity method: summing the concentrations of components with the same effect and comparing them to threshold values.
Component categories, concentrations, and any specific limits.
Eye damage/irritation
Similar collectibility logic and cross-class rules to leather.
Component categories and concentrations
Sensitization
Classification occurs when the component exceeds a defined threshold concentration; very low thresholds apply to some substances.
List of sensitizing ingredients and concentrations.
CMR (carcinogenic, mutagenic, reproductive toxic)
Direct classification of the mixture if the component exceeds the cutoff value.
Component category and concentration
Target organ toxicity
Comparison of component concentrations with class-specific thresholds; specification of the affected organ.
Component category, target organ, concentration
Aspiration injury
The total concentration of the relevant components and the viscosity of the mixture are evaluated together.
Component concentrations and mixture viscosity
Harmful to the aquatic environment
M-factor weighted total method; separate calculations for acute and chronic cases.
Component categories, M factors, concentrations
Physical injuries
It relies largely on the measurement of the mixture itself; in some cases, inferences can be made from the components.
Flash point, oxidizing agent content, test data.
Where are the limits of the calculation?
Most health and environmental hazards can be determined by calculation. However , many physical hazards require measurement of the mixture itself : flash point, oxidation, explosive properties, etc. A well-designed system clearly shows the user this distinction: which classes have been calculated, which require measurement, and which data is missing.
This transparency is critical because the outcome provided by the system is a decision support , not a statement of responsibility. The final classification is always confirmed by an expert's assessment.
5. The benefits of prescription classification for businesses.
In the classic method, a formulator only learns the product's hazard profile after producing and testing a sample. If the hazard class turns out to be heavier than expected, the recipe is changed, and the cycle starts over. Each cycle means raw material consumption, laboratory time, external testing fees, and often weeks of delay.
The ability to calculate from the prescription reverses this cycle. The classification is known when the formulation is designed :
01
Instant feedback
When a formulator changes the ratio of an ingredient, they see on the same screen how the hazard profile of the mixture changes. Trial and error is done on the screen instead of in physical production.
02
Threshold awareness
The system shows which component triggered the classification by exceeding a specific threshold. The information, "If this component falls below 1%, this pictogram will disappear," directly guides the formulation decision.
03
Scenario comparison
Several alternative formulations of the same product are compared side-by-side in terms of hazard profile and cost. The choice is based on data.
04
Raw material change control
When a raw material is to be changed due to a supply problem, its impact on the label and safety data sheet is assessed before the decision is made.
05
Supplier data exchange
When a supplier updates their safety data sheet, the classification of all products containing that substance is recalculated, and those affected are listed.
06
Impact of legislative change
When a new harmonized classification is published, a single query can identify which products in the portfolio are affected.
Tangible achievement
To the extent that the physical trial-test cycle is eliminated, raw material consumption, laboratory workload, external testing costs, and time to market are directly reduced. In chemical companies that produce customized formulations for numerous customers, this means performing dozens of trials on screen every month.
6. Output of the calculation
The output produced by the classification engine is fed directly into the label and safety data sheet:
Damage classes and categories, along with triggering components.
Hazard (H) statements and additional hazard statements
Classification rationale report: which class was determined by which method, which data, and which threshold?
Missing data report: which component lacks data, which class requires measurement?
The version and date of the calculation; which GHS revision it was based on.
The last point is often overlooked but is crucial in audits: having a documented justification for the classification . Being able to answer the question, "Why did you classify this product this way?" with a report showing all the steps of the calculation is a far stronger position than relying solely on the expert's memory.