40 CFR Parts 63 (Section (Section 63.1440 to 63.6175) continues coverage on the United States Environmental Protection Agency. in this volume, you will find rules, processes, procedures, and regulations relating to hazardous air pollutants, national emission standards, emission limitations, testing, maintenance, operation, and compliance requirements for primary copper smelting, secondary aluminum production, primary lead smelting, petroleum refineries, sulfur recovery units, catalytic cracking units, municipal solid waste landfill, and more. Environmentalists, and ecological scientists, oil and gas refinery workers, testing engineers, tire manufacturer personnel, environmental inspectors, municipal public works personnel, and compliance officers may be interested in this volume. Code of Federal Regulations Title 40, Volume 13, July 1, 2015 Containing parts Part 63, §§ 63.1440 to 63.6175 Part 63; NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED)