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CLP labels for a custom blend of fragrance oils

Published 21 September 2026; rules last checked 25 September 2026. A labelling reference, not legal advice.

A blend of two fragrance oils is a new mixture with its own classification, and neither supplier's document describes it. CLP puts the duty to classify a mixture on the person who places it on the market (Article 4(1)), and you may only reuse a classification from up the chain if you do not change the composition (Article 4(6)). Mixing two oils changes it. Putting the two oils' labels together is not a classification. The routes that work are: a classification for the blend from a supplier who offers one, a blend bought ready-mixed with its own data, a person who can apply the Annex I methods to the two compositions, or one oil per product.

Why two documents do not add up to one label

A supplier's CLP document classifies that oil in wax at a stated percentage, using the concentration of each hazardous component in the finished product (Article 11(2)). Blend two oils and every one of those concentrations changes, in three ways at once:

• The same substance from both oils adds up. Suppose each oil, at the load you use, contributes a category 1 skin sensitiser at 0,7 % of the candle. Neither document shows H317, because 0,7 % is under the 1,0 % limit in Table 3.4.5 and each shows EUH208 instead. Together the substance is 1,4 % of the candle, over the limit, and the blend is classified Skin Sens. 1, with the pictogram and H317 that neither oil carried.
• Different sensitisers are judged one by one. Section 3.4.3.3.1 classifies the mixture when at least one ingredient is at or above its limit, so every sensitiser from either oil that is over 1,0 % (or 0,1 % for a sub-category 1A substance) counts, and every one over the Table 3.4.6 limit (0,1 %, or 0,01 % for 1A) must be named on the label: in the EUH208 line if the blend is not classified as a sensitiser, and by name alongside the classification if it is (Annex II, section 2.8). The Contains line of a blend is usually longer than either oil's.
• Aquatic hazards are summed across substances. Section 4.1.3.5.5 classifies a mixture for the aquatic environment by adding the contributions of its components, weighted by category and M-factor. Two oils that each sit below a threshold can sit above it together.

And the opposite happens too. If a candle is 5 % oil A and 5 % oil B, each oil is at half the load its document describes, and a hazard the document shows at 10 % may not be present at 5 %. A label that copies both documents over-warns for that and under-warns for the additions above. That is why the blend has to be evaluated (Article 9(1)) against the Annex I criteria from the information on its components (Article 6(1)), rather than assembled from two labels.

What the tool does, and what it will not do

Our candle tool assembles a label from a classification you enter: it puts the right pictograms, one signal word, the exact hazard statements, the EUH208 line and the supplier block together, and applies the UFI rule for the region. It does not compute a classification from component concentrations, on purpose. The summation rules, the generic concentration limits and the M-factors are the part of CLP where a small arithmetic slip produces a confidently wrong label, and a tool that guessed at them would be exactly the wrong kind of help. For a blend, the classification you enter must be the blend's.

The product identifier for a blend

Article 18(3) requires, for a mixture, the trade name and the identity of the substances that contribute to its classification for the listed health hazards, skin sensitisation among them, up to four names unless more are needed to reflect the hazards. For a blend those substances come from both oils, chosen as the ones primarily responsible for the major health hazards (Article 18(3), last subparagraph). The blend's own name is yours to choose; the substance names are not.

Getting to a classification

• Ask the supplier. Where both oils come from one supplier, ask for data on the blend at your load; some provide it or a calculator, because they hold the full compositions.
• Buy the blend. A ready-made blend sold as one fragrance oil comes with one document, and the question disappears.
• Have it classified. A person who can apply Annex I to the two compositions (from the suppliers' safety data sheets) can produce the classification; that is the job CLP describes in Articles 6 and 9.
• One oil per product. The simplest route for a small range.

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