The safety aspect of essential oils is an important issue, which has attracted a fair amount of media interest. Some oils, such as pennyroyal, should be withdrawn from general distribution, while certain others such as white camphor should be used in moderation only. However, the potential dangers of any essential oil depends entirely on how much is used and under what circumstances. Precise instructions and information on their usage, their exact botanical origin and up to date safety data should be taken into account by suppliers.

Highlighting the potentially harmful oils is a very valuable exercise. On the other hand, it is a pity if it leads to an over-emphasis of the hazards of using any type of essential oil.
In reality, many household products such as detergents, bleach or oven cleaner (as well as the more common remedies such as aspirin or paracetamol) can be harmful if they are used in the wrong way or by the wrong hands. I think the most important factor, with regards to the safety of essential oils at home, is that of knowing exactly how and when to use them; any contra-indications that apply to particular ones and their precise botanical origin and source.

Before using any essential oils, it is always best to take the following simple precautions:

Do not use essential oils at home to treat serious medical or psychological problems. If in doubt consult a doctor or qualified therapist. Some complaints, especially of a chronic or long-standing nature are best dealt within a professional context.
Do not take any essential oil internally. They are extremely concentrated and can be harmful.
In general, essential oils should not be applied undiluted to the skin, although there are exceptions to the rule.
Do not use essential oils on young babies (under one) and use the essential oils at half the recommended dilution for children under twelve. Some oils are contra-indicated for infants or young children under six.
Some oils are contra-indicated during pregnancy, others during the first four months only. Always use the essential oils at half the recommended dilution during pregnancy.
Some oils should be avoided when in combination with alcohol or homeopathic treatments and in cases of high blood pressure, epilepsy or allergies.
Store essential oils in dark bottles, away from light and heat (best kept refrigerated) and well out of reach of children.