Flash point, and why it is on the safety sheet
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The one number on a fragrance oil's paperwork that matters on the day you pour, and the one most often misunderstood.
What flash point is
The lowest temperature at which a liquid gives off enough vapor to ignite in the presence of an ignition source.
It is a handling and shipping property. It tells you how to treat the oil in the bottle and in the melt pot.
Where to find it
On the safety data sheet, which the supplier must make available under the OSHA hazard communication requirements.
Ask for it if it is not on the product page, and keep it. It is also where the hazard classification and the handling precautions live, and both matter more than the flash point on its own.
What it means for adding fragrance
Do not add fragrance to wax that is above the oil's flash point. Not primarily because it will ignite in the pot, which is unlikely in an open melt at normal temperatures, but because you are heating a volatile liquid past the point where it readily vaporizes, and what vaporizes is the scent you paid for.
The common flash points for candle fragrance oils sit comfortably above normal soy pour temperatures, so the usual practice of adding at the supplier's recommended temperature stays well clear.
The real hazard is a hot plate or a naked flame near an open pot, not the wax itself.
It is not the same as the burn
A low flash point does not mean the finished candle is dangerous. In a burning candle the fragrance is bound in the wax and delivered through the wick, which is a completely different situation from a bottle of neat oil near a heat source.
Flash point governs your workshop. Burn testing governs the candle.