Reading an SDS for an Essential Oil You Bought

Pull up the SDS for a synthetic surfactant next to one for lavender oil and you'll notice section 3, composition, looks nothing alike. The surfactant has one clean entry: a name, a CAS number, a percentage. The lavender oil might list a dozen compounds, several without exact percentages, and sometimes a CAS number for the oil itself that barely tells you anything useful. That's not a lazier document, it's a different kind of material, and reading it correctly matters for your filing.

Why a natural material's SDS looks messier

A synthetic ingredient is a single, defined molecule made the same way every time. Its SDS can state exact composition because the manufacturing process controls for it.

An essential oil is a mixture of dozens to hundreds of naturally occurring compounds, and the exact ratio shifts with growing region, harvest timing, weather that year, and distillation method. So a lavender oil SDS might report a CAS number for "Lavandula angustifolia oil" as a whole, and then, in the composition section, list the major constituents (linalool, linalyl acetate, and so on) with approximate ranges rather than fixed numbers. That's expected. It reflects how the material actually varies, not a supplier being vague on purpose.

The part that matters most right now: allergens

Section 3 of an essential oil's SDS is often where you'll find the clearest statement of which fragrance allergens are naturally present and roughly how much. This has become more important with fragrance allergen disclosure rules tightening. In Canada, List 1 allergens become mandatory on the Cosmetic Notification Form and label on April 12, 2026, and the expanded List 2 becomes mandatory August 1, 2026. Disclosure triggers at concentrations above 0.001% (10 ppm) in leave-on products and above 0.01% (100 ppm) in rinse-off products.

Essential oils are exactly where this bites people, because compounds like Limonene, Linalool, Citronellol, Geraniol, and Eugenol occur naturally, sometimes at meaningful levels, in common oils like citrus peels, lavender, and clove. If your SDS gives you constituent percentages, you can multiply that percentage by your essential oil's use level in the finished formula to see whether you cross a disclosure threshold. If the SDS doesn't break out allergen constituents at all, that's worth going back to the supplier for, because "it's natural" isn't an answer a regulator will accept in place of the actual number.

What to check for, section by section

SDS section	What to look for in an essential oil SDS
Section 1: Identification	Confirm the botanical (Latin) name matches what you think you're buying; "lavender oil" alone is ambiguous between species
Section 3: Composition	Look for named allergen constituents with percentage ranges, not just a single CAS for the whole oil
Section 9: Physical/chemical properties	Useful for stability and storage, less relevant to filing but good practice to keep on file
Section 11: Toxicological information	Sometimes references sensitization data tied to specific constituents
Section 16: Other information	Revision date; essential oil SDSs should be refreshed periodically since sourcing and testing standards evolve

When one CAS number isn't enough

Some botanical extracts and essential oils don't have a single clean CAS number at all, or they have one for the whole oil and separate ones for named constituents. Don't be surprised if your INCI mapping ends up listing both: the oil itself as the INCI ingredient, with allergen constituents called out separately for disclosure purposes once you cross a threshold. This dual listing isn't a paperwork error, it's how natural complex mixtures are meant to be handled on both an SDS and a notification.

Keeping this manageable across a whole product line

If you make several products that share a few essential oils in different ratios (a lot of soap and lotion lines do exactly this), it's worth building a simple reference table once: each oil, its supplier SDS, and the allergen constituents it carries with approximate percentages. Then when you formulate a new product, you're doing arithmetic against numbers you already have rather than re-reading a full SDS from scratch every time.

This is essentially what Cosmetic Comply automates on the ingredient side. Feed in your formula and it maps each ingredient, including essential oils and botanical blends, to INCI and CAS, carries supplier concentrations through the math, and flags where an allergen threshold is likely crossed so you're not doing that multiplication by hand for every SKU.