Part 523 - Environment, Energy and Water Efficiency, Renewable Energy Technologies, Occupational Safety, and Drug-Free Workplace Subpart 523.1 - Sustainable Acquisition Policy 523.101 General. 523.102 Definitions. 523.103 Applicability. 523.104 Procedures. 523.105 Sustainability Exceptions. 523.106 Compliance Monitoring and Reporting. Subpart 523.3 - Hazardous Material Identification and Material Safety Data 523.303 Contract clauses. 523.370 Solicitation provision. Subpart 523.4 - Use of Recovered Materials and Biobased Products 523.404 Agency affirmative procurement programs.