Legal Proceedings And Contingent Liablities (Tables)

6 Months Ended

Nov. 30, 2011

Legal Proceedings And Contingent Liabilities [Abstract]

Summary Of Employee Exposure Standards By Regulatory Agencies

Occupational Safety and Health Administration	5,000 ng/m³
National Institute for Occupational Safety and Health	1,000 ng/m³
California Environmental Protection Agency	200 ng/m³