Mainly I am concerned about the various plasticizers being released
Most EVA resins are internally (polymer chain) plasticized. The
phthalate plasticizers are more broadly used in polyvinyl chloride
(PVC) resins to control softness and elasticity.
The DOP is more likely to migrate than vaporize. When the DOP
migrates from the PVC on your car's dashboard to the foam underneath,
the resulting loss of elasticity and volume, together with oxidation,
and yes, some vapor loss of DOP, causes it to crack.-Jitney