11.   The patent covers an improvement on a substance called Z-sorb, which removes highly corrosive sulfur compounds from gasoline.

12.   The work focuses on two types of sulfur compounds known as sulfates and sulfides.

13.   The vine, the archeologists found, contains sulfur compounds, and the process only works in hot weather, so the process is closely analogous to modern rubbermaking.

14.   The sulfur compounds would be especially toxic, Sharpton said.