An adjuvant is defined as a "substance other than water, without significant pesticidal properties, which enhances or is intended to enhance the effectiveness of a pesticide when it is added to that pesticide" (The Plant Protection Products (Basic Conditions) Regulations, 1997 refer). Adjuvants, therefore, do not have pesticidal activity and are not classified as plant protection products.

However, as with plant protection products, adjuvants are subject to a series of regulations to ensure that these materials are used safely and effectively, and include:

(i) The Control of Pesticides (Amendments) Regulations, 1987;
(ii) The Plant Protection Products (Basic Conditions) Regulations, 1997;
(iii) The Health and Safety at Work Act, 1974;
(iv) The Control of Substances Hazardous to Health Regulations (COSHH), 1999
(v) The Chemicals (Hazard Information and Packaging for Supply) Regulations, 2002 (commonly referred to as the CHiP3 regulations);
(vi) Proposed REACH regulations

These regulations determine:
(1) Toxicological classification – determining the type of protective clothing that may be required when using the adjuvant;
(2) Environmental classification – determining the type of environmental precautions listed on the adjuvant label;
(3) An adjuvant is used in accordance with the published conditions of use of the adjuvant as published by the Pesticide Safety Directorate (PSD).

In order that adjuvants may be used with plant protection products, the adjuvant must be authorised by the PSD, and be specified in ‘The Official List of Adjuvants’, published by Ministers. For the adjuvant to be listed, a set of data requirements have to be met and than evaluated by the PSD in order to determine the safe conditions of use of the adjuvant with a plant protection product.

This data can include mammalian toxicity data, ecotoxicity data, physio-chemical properties of the adjuvant, residue data and data relating to the manufacture and technical specification of the adjuvant.

Adjuvants are then classified by PSD into the following product groups:
- extending agents
- wetting agents
- sticking agents
- fogging agents
The other regulations stated also control how adjuvants maybe stored, used, the type of protective clothing used and environmental precautions that have to be considered.

There is also a further new set of regulations currently being proposed by the European Commission – the REACH Regulations (the Registration, Evaluation and Authorisation of Chemicals).
It is proposed that this set of regulations will apply to all chemicals, depending on how much is produced or if a chemical is of ‘very high concern’.

Manufacturers of these chemicals must:
(1) produce mammalian and ecotoxicity data;
(2) produce a human health & environmental risk assessment related to all intended uses of the proposed chemical;
(3) produce a chemical safety report.

Interagro also has a strong efficacy trials programme, which involves trials programmes being carried out with plant protection product manufacturers as well as distributors.

This efficacy trials programme also extends to Interagro’s presence throughout Central Europe and Eastern Europe, where, in certain countries, official efficacy trials have to be carried out before an adjuvant can be registered.

Adjuvants are therefore subject to a series of wide-ranging regulations and this has been one of the main drivers leading to the development of adjuvants which are practically non-toxic.

Such an example is Toil which is not subject to a COSHH assessment, is practically non-toxic to fish and is not subject to the CHiP 3 Regulations.