Alpha-pinene in the home comes from the Christmas tree and tubes of tree scent that are sold to make those artificial trees seem real. Related terpenes are found in many spices and flavors, like limonene in orange zest from orange peel (it’s in the cranberry sauce) and eucalyptol and camphor in rosemary (turkey stuffing). Although harmless in the home, OSHA and NIOSH recommend limiting workplace exposure to alpha-pinene and related terpenes to 100 PPM average over 8 h, although most European countries limit exposure to 20 PPM. Camphor is more harmful; exposure is limited to 2 PPM in most European countries. Exposure to limonene is best limited to 5-30 PPM in the US and Europe. Many of these terpenes, especially limonene, are used as cleaning solvents sometimes as a component of a formula made in water with surfactants. Terpenes are highly susceptible to oxidation, by both oxygen and ozone, which produces peroxides/hydroperoxides that are far more harmful than the parent terpene. You can test cleaning formulas that have been stored for peroxides using inexpensive starch iodine paper. It’s wise to put expiration dates on all terpene-containing formulas to remind when retesting is necessary. Look for antioxidants, like BHT, to stabilize the formula.
