D-Limonene.

Also known as Orange Oil or Lemon Oil, this was the most difficult for me to research. It is labeled as 100% Natural, Earth Friendly, Non-Toxic and Biodegradable. I've seen it marketed as 'Food Grade' but is it safe?

D-Limonene is the oil extracted from the peel of several citrus fruits. It is, without a doubt, Earth friendly, natural and biodegradable. The cleaning properties never cease to amaze me. When we compare it to some of the products it could replace such as; Acetone, Methyl Ethyl Ketone, Mineral Spirits and Toluene, it seems very safe. The National Center For Biotechnology Information indicates that D-limonene has well established chemo-preventive activity against many types of cancer. The question is, is it safe for humans when used for cleaning?

With a health 2 rating on the MSDS safety sheet, research shows that D-Limonene is a skin and eye irritant. There are also indications that it may be a mild respiratory and digestive tract irritant.

Animal testing indicates the possibility of carcinogenic activity. Male rats showed increased incidences of carcinomas of the kidney, while there was NO evidence of that activity in female rats, male mice or female mice.