Unlike industry-standard petroleum-based dyes, this shirt is dyed with madder root and logwood.
Madder root is one of the oldest natural dyes, known for its ability to make beautiful reds. It has been safely used for thousands of years, since at least ancient Egypt (cloth dyed with it has even been found alongside the possessions of King Tut).
Logwood dye is extracted from the heartwood of logwood trees. It has been safely used in Europe since the 1500s, and by the Mayans for hundreds of years before that.