Overview
These four phthalates are plasticisers, added to materials to make them soft and flexible. They are toxic to reproduction and act as endocrine disruptors. RoHS added them in 2015, an expansion often called RoHS 3.
Where they're restricted
Under RoHS each of DEHP, BBP, DBP and DIBP is capped at 0.1 percent by weight per homogeneous material. They also appear on the REACH Candidate List as substances of very high concern, and feature on the REACH Authorisation and Restriction lists. See SVHC and the REACH annexes for those mechanisms.
Typical uses
The main job of these phthalates is softening flexible PVC. They also turn up in adhesives and coatings. Substitution toward other plasticisers has been widespread, but they remain common in legacy and imported parts.
Because phthalates migrate between materials and are easy to miss, suppliers often confirm them through a full material declaration rather than a single test.
Note: general educational information, not legal advice. Check the official source before relying on it.