Each of these ingredients, and others, modifies the spray solution itself to improve such properties as spreading, penetration, droplet size or other characteristics.
In the United States, agricultural tank adjuvants are essentially unregulated except in a few isolated cases.
Supporting the activities of ASTM is the Council of Producers & Distributors of Agrotechnology (CPDA), an organization of inert (or other) ingredient and adjuvant manufacturers.
This much more stringent requirement prevents both the widespread use and questionable content present in the United States.
In the UK, the Chemical Regulations Directorate (CRD), part of the Health and Safety Executive, oversees the use of adjuvants.
The Council of Producers & Distributors of Agrotechnology offers participating companies the ability to self-certify their spray adjuvant products in the USA.