To quote the legendary Roseanne Roseannadanna, “It’s always something.”

Or, to quote Jody Shaw, manager of technical marketing and product research for U.S. Steel, from a recent presentation to the Environmental Protection Agency and the National Highway Traffic Safety Administration (NHTSA), “In order to comply with the tailpipe-only regulations, automakers may inadvertently select materials that increase the life cycle carbon footprint of the vehicle. While other materials”—as in aluminum and magnesium—“may provide mass advantages in vehicles, the resulting improvement in fuel economy may not offset the energy use and CO₂ emissions that result form manufacturing and recycling of a vehicle containing the replacement materials.”

Shaw’s recommendation? “To address these unintended consequences, a Life Cycle Assessment approach is needed.”

The North American steel industry is recommending that the emissions measurements start when the materials are still raw and conclude only when they are recycled. At which point, steel looks really, really good.