It consists primarily of monoterpenes, terpene alcohols and oxygenated cyclic compounds. Limonene fraction of terpenes and terpenoids obtained from turpentine oil or citrus oils by fractionationor isomerization of other terpene fractions. Because limonene is a major component of orange oil and other citrus oils, it is marketed as a natural, safer cleaner. Limonene is known to be a dermal irritant and sensitizer. Oxidation is known to cause potent respiratory sensitizers.
Recent studies indicate there are other concerns.
It has been found that limonene in the presence of ozone forms submicron particles. Fragrance chemicals ''which are less frequently reported and less documented as consumer allergens''.