Found this in Dr. Mohammed Ali Al-Bayati path & tox pdf:
Boldest by me for emphasis...
http://www.omsj.org/2012/Al-Bayati-Keith-Report-Feb-13-2012-F.pdf
Snipped:
Most of the technical grade TCE sold in the USA contains about 94% TCE and 6% stabilizers such as epoxides and amines to prevent dehydrochlorination of TCE and the reaction of TCE with metals. However, no dioxane was present in Keiths blood and tissues.
These data indicate that TCE used in Keiths case was not purchased to clean metals and it was likely used as a cleaner for photographic film.
Keiths mother found a plain vanilla envelope inside the screen door of her house on April 9, 1992, which is about 6 years after Keiths death. It contained 5 crime-scene photos showing Keith was hanging from a tree. The police department conceded that they were copies of original police photos, but they had no idea where they came from.
It is possible that there is a link between the individual who produced a copy of the crime- scene photos and the individual who purchased the TCE used in Keiths case. TCE is used as cleaner for photographic film (Sections III & IV).
4)
The estimated volume of xylene, ethylbenzene, and toluene mixture ingested by Keith is 1.7 mL. It consists of 73.9% xylenes, 20.5% eththylbenzene, 5.52% toluene, which is similar to the composition of the technical grade xylene that contain about 80% xylenes, 20% ethylebenzene as well as a small quantity of toluene. It is possible that the technical grade TCE used in Keiths case also contains 2% technical xylene or the technical grade xylene was added to TCE to enhance their solubility in water.
Xylene is also used as a solvent in the printing industry (Sections III & IV).