Unfortunately, linalool can be a problematic ingredient for some people. When linalool comes into contact with oxygen, it breaks down and becomes oxidized, which can cause an allergic reaction. Manufacturers do include other substances in the products to delay this oxidation process, but allergenic substances can still be formed from linalool when it is stored.
Dermatologist Johanna Bråred Christensson explains, “One way of trying to minimize exposure to oxidized linalool is to avoid buying large packs of soap and shower cream, and always to replace the top after using a bottle.”
In conclusion, the safety of linalool depends on whether this ingredient is used in its natural form or as a synthetic fragrance. Linalool as a natural compound of an organic essential oil may provide anti-inflammatory effects, but the synthetic version can possibly lead to skin irritation or allergic reactions.
References: Wikipedia, “Linalool”, Wikipedia, “Terpene”, Cosmetics Info, “Linalool”, Medical News Today, “Widely Used Fragrance Ingredients In Shampoos And Conditioners Are Frequent Causes Of Eczema”, 2009, Naturally Free Life, “Why Essential Oils Work: The Chemistry of Linalool”, 2016, AANA J. 2008 Feb;76(1):47-52, Phytomedicine. 2002 Dec;9(8):721-6, Dr. Axe, “Dangers of Synthetic Scents Include Cancer, Asthma, Kidney Damage and More”.