Limonene is abundantly present as a constituent of essential oils. In the portfolio for the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) program, about 60 % of natural complex substances (NCS) registered contain D- or L-limonene in levels varying from traces to occasionally over ninety percent. The most prominent examples are the citrus oils, in which D-limonene dominates the properties for hazard classification. However, even when present at low levels, limonene can contribute significantly to the hazard classification of the NCS under the current EU rules. In particular, its volatility determines the flammability and, as a pro-hapten (Lepoittevin, 2006; Smith and Hotchkiss, 2001), it triggers concerns of skin sensitization. Furthermore, for aquatic species it is a very toxic substance regulated as acute and chronic category 1. The basis for the chronic classification was the assumption that limonene is not readily and rapidly degradable. Indeed, in the absence of experimental data for chronic toxicity end points, theoretical calculations predicted a potential for bio-accumulation with a high degree of toxicity for aquatic species. These results then led to the classification of limonene as chronic category 1, which triggers stringent precautionary measures for storage and handling.


Therefore, several years ago, the European Federation of Essential Oils (EFEO) and IFEAT initiated a project to experimentally determine the long term aquatic properties of limonene based on a robust scientific approach and protocol. The results of this initiative are provided here in the form of the poster as presented in Rome in May 2018 at the 28th Annual Meeting of the Society of Environmental Toxicology and Chemistry ( by Paul Thomas from the Consultancy for Environmental & Human Toxicology and Risk Assessment (CEHTRA, They offer significant relief and are a solid basis for a reclassification of limonene as chronic category 3 instead of category 1.


In parallel and in order to officially validate this re-classification proposal, the Dutch competent authorities have submitted the harmonised classification and labelling (CLH) dossier to The European Chemicals Agency (ECHA). Technical completeness has been approved and as of 22nd May 2018 the file has moved on to the public consultation phase which will last for 60 days. The full CLH dossier for limonene is also available here:


Further information is available via the following link:


Please contact [email protected] in case of any questions or comments.


Click on the image to download the Limonene Poster as a .pdf file.

History of the 40 years of IFEAT!


Read Peter Greenhalgh’s “History of IFEAT” series. The full version in a book was given as a gift at the Athens Fortieth Anniversary Conference 2017. Each of these articles has been included in past issues of IFEATWORLD.



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