What does California's trauma scene registration actually mean for my cleanup?

It means the work is performed inside a regulated system rather than by an unlisted operator. Practitioners who clean trauma scenes register with the California Department of Public Health, follow the state's requirements for handling and packaging trauma scene waste, and transport that waste under manifest to permitted treatment or disposal facilities. For a family, the practical tests are simple: the company can name its registration, the estimate itemizes the removal and disinfection, and the job's paperwork includes the manifest. If any of those three cannot be produced, the quote is for a different and lesser thing than the regulated service, whatever its price says.