DINP is typically a mixture of chemical compounds consisting of various isononyl esters of phthalic acid, and is commonly used in a large variety of plastic products.

The European Union has set a maximum specific migration limit (SML) from food contact materials of 9 mg/kg food for the sum of diisononyl phthalates and diisodecyl phthalates.

[2] DINP is listed as a substance "known to the State of California to cause cancer" under Proposition 65 legislation.

[3] Studies find that exposure to environmentally relevant concentrations of DINP in zebrafish disrupt the endocannabinoid system (ECS) and affect reproduction in a gender specific manner,[4] and have other adverse effects on aquatic organisms, as DINP upregulates orexigenic signals and causes hepatosteatosis together with deregulation of the peripheral ECS and lipid metabolism.

[5] The ECHA's Risk Assessment Committee (RAC) has concluded, on March 7, 2018, that Di-isononyl phthalate (DINP) does not warrant classification for reprotoxic effects under the EU's Classification, Labelling and Packaging (CLP) regulations.