Three signs indicate that US Environment Protection Agency is taking significant steps toward strict regulation of nano-materials under the Toxic Substances Control Act, TSCA.  

This is revealed in an advisory paper about Environmental and toxic tort published by legal web site Alston + Bird.  

Protective clothing
The agency recently issued new rules for manufacturers of carbon nanotubes as regards their employees' protective equipment and clothing. Also, the surveying of workers' health in industries dealing with such nanotubes, nanoscale clays and nanoscale alumina may become mandatory, as may the reporting of results from these tests. 

EPA is, according to one source, in the process of developing a proposal to establish reporting requirements for certain nanoscale materials” under TSCA.