I have heard that the color of tren comes down to a few factors. One of the factors could be the quality or age of the raw powder. Anoth factor can obviously be how the tren is made. Tren is a compound that will change colors when it becomes more oxidized. If you heat tren too long it will undergo more oxidation and therefor have a darker tint to it. Also if the raw is added to by hot oil this would cause much more rapid oxidation vs putting it in cooler oil and letting it slowly heat. I have not seen any proof that the oxidation will change the potency of tren though so the color really shouldn't effect it. Also the carrier oils would obviously change the overall color, as they come in different shades. Hope this helped
Controversy first arose when the French-owned and Montgomery County, Maryland -based Keolis (already operating Virginia Railway Express trains) was the only bidder for the contract. The bidding process was suspended in the fall of 2010 due to lack of competition. Before bidding reopened in 2011, Maryland passed a law (at the request of Leo Bretholz and other Holocaust survivors) requiring Keolis's majority owner, SNCF (currently solely owned by the French government)  to fully disclose its role in transporting Jews to concentration camps during World War II (while SNCF was under control of the Nazi government), to the satisfaction of the Maryland state archivist, before Keolis would be allowed to place a bid for MARC service. Keolis faced similar issues while bidding for VRE operations in 2009, but in the end, they were allowed to run VRE.