What are the standard regulations on document shredding?
In general, a business is responsible for taking reasonable precautions with their customers personal information. The FTC has been aggressively pursuing companies who fail to do so under the Fair and Accurate Credit Transaction Act (FACTA). To help protect yourself and your customers I would recommend using a AAA certified shredding service. Here is a good article on the history of shredding laws: http://www.shrednations.
