Marlene Engelhorn, an Austrian heiress who inherited $27 million from the company that produced Zyklon B, the poison used in Nazi gas chambers, is joining a flotilla aiming to break Israel’s blockade of Gaza, according to The Jerusalem Post.

Engelhorn is a descendant of the German industrialists who founded BASF, which merged with IG Farben in the 1920s. Under the Nazi regime, IG Farben manufactured the cyanide-based gas used in the Holocaust.

Though IG Farben was dissolved after World War II, BASF was reestablished in 1952 and remained under Engelhorn family control until the mid-1990s, when it was sold for more than $4 billion.