That’s the question raised by a study presented at the American Chemical Society’s conference in California this week. Fish exposed to a water-soluable type of the carbon molecule at a concentration of 0.5 parts per million developed “significant” brain damage in just 48 hours, although researchers don’t yet know how the buckyballs are causing the damage. The research underscores how little scientists know about the effects that buckyballs and carbon nanotubes–materials touted for their potential in a wide range of applications–could have not just on fish and other animals, but humans as well. At a conference last September on the space elevator–a space transportation concept that would utilize a ribbon 100,000 kilometers long made of carbon nanotube fibers–one presentation by Ron Morgan of Los Alamos National Laboratory covered how little people know about the health risks of carbon nanotubes. His general advice to nanotube researchers: “don’t be the guinea pig!”