I offer a "6" for the actual answer I wanted to give ("possibly carcinogenic")-- for the answer I was constrained to give ("suggestive"), I'd rate my confidence at an 8-- there is a wealth of "suggestive" evidence, and while each of the exculpatory theories offered in the white paper would dissuade me from ever concluding 1,3-D is "likely," none of it lowers my appraisal below "suggestive" to "not likely."
ADDENDUM ADDED MAY 1 BASED ON ROUND 4:
I have changed my degree of confidence from 6 to 9 based on Round 4. "Not likely" (the opposite of my view then) has become in my mind even less credible as I read and engaged with the other comments.