Nanomaterial health effects--Part 2: Uncertainties and recommendations for the future.

In this paper, we summarize some of the key data gaps, uncertainties, and unknowns that need to be addressed to develop adequate risk assessments for nanomaterials. We make recommendations to take timely and appropriate public health precautions. We also briefly discuss nanotechnology applications for food and food packaging, and describe the University of Wisconsin-Madison's Nanotechnology in Society Project.