Of course they're "chemicals." So are salt, water, and vinegar.
It's one thing thing if you are allergic or hypersensitive to one of these, but lots of bakers get vanilla on them, and they ain't dyin'. I suppose if someone consumed an entire quart of vanilla extract in one shot, it could cause some damage, but that would be stupid (not to mention an entirely different thread).
So, while they are chemicals, and some people might react to them, I'll go out on a limb and say the point is:
1) they're naturally occurring substances
2) are probably safe for most people
3) are probably damaging to the environment
4) probably wash off much easier than comercially manufactured insect repellents
Granted, not everything that ocurs naturally is safe for you, but if it's safe for human consumption, I'll take my chances rubbing it on my skin.
Like I said, most of these essential oils and natural supplements and the like have never been tested, not even for their advertised uses. That is because it is not required by the FDA; there is very little regulation of the industry. It's a loophole that allows people to sell all kinds of snake oil home remedy crap without ever testing their safety. In the links I provided in the prior post, there are lots of examples of natural supplements causing deaths even when they are used as directed.
Below are some hazard data from the Material Safety Data Sheet for limonene, the main constituent of citrus oil. You can look up similar safety data for all the oils cited above. I'd encourage anyone who thinks about rubbing these all over their skin to make sure they inform themselves first, rather than just go out on a limb and take chances just because they are "natural".
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HAZARDS IDENTIFICATION
Emergency Overview
OSHA Hazards
Combustible Liquid, Target Organ Effect, Skin sensitiser, Irritant
Target Organs
Kidney
GHS Classification
Flammable liquids ( Category 3 )
Acute toxicity , Oral ( Category 5 )
Skin irritation ( Category 2 )
Eye irritation ( Category 2A )
Skin sensitisation ( Category 1 )
Acute aquatic toxicity ( Category 1 )
Hazard statement(s)
H226 Flammable liquid and vapour.
H303 May be harmful if swallowed.
H315 Causes skin irritation.
H317 May cause an allergic skin reaction.
H319 Causes serious eye irritation.
H400 Very toxic to aquatic life.
Precautionary statement(s)
P273 Avoid release to the environment.
P280 Wear protective gloves.
P305 + P351 + P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.