As of October 2003, no toxicological information available. There are a two reference to Thidiazimin as a Protox inhibitor - also known as a photobleaching herbicide.

Environmental (click on for all fluorinated pesticides)

Phototoxic Pesticide. Light-dependent peroxidizing herbicides (LDPHs). US EPA identified the organofluorine herbicides Acifluorfen, Azafenidin, Carfentrazone-ethyl, Flumiclorac-penty, Flumioxazin, Fluthiacet-methyl, Fomesafen, Lactofen, Oxadiargyl, Oxadiazon, Oxyfluorfen, Sulfentrazone, Thidiazimin as phototoxic pesticides that act by inhibiting protoporphyringen oxidase in the heme and chlorophyll biosynthetic pathway. [10 out of the 13 pesticides that EPA identified are organofluorines].
SEE http://www.fluoridealert.org/pesticides/PHOTOTOXICITY.PAGE.htm
Ref: December 11, 2001 - US EPA. Revised Environmental Fate and Effects Division Preliminary Risk Assessment for the Oxyfluorfen Reregistration Eligibility Decision Document - also at: http://www.epa.gov/oppsrrd1/reregistration/oxyfluorfen/oxyefedchap.pdf