VDCs cause malformed vascular development in the ISV, DA and CVP. Tg(kdrl:EGFP)mitfab692 embryos were treated with vehicle (control; A, E) or chemicals from the ToxCast Phase 1 chemical library (B-D, F, G) from 3 hpf to 72 hpf. Lateral view with anterior to the left and dorsal to the top. Vascular defects include non-overlapping ISVs (B), or thin and underdeveloped ISVs (C), expanded DA (D), and less condensed CVP (F), or misshapen CVP (G) and are marked with yellow lines or arrows. A common vascular-related phenotype, which is characteristic of cardiotoxicity, is pericardial edema (H; black arrowhead). Scale bar = 100 µm.