This guidance from The Advisory Committee on Dangerous Pathogens offers technical information on the design, management and operation of containment laboratories, especially Containment Levels 2 and 3. The guidance expands and explains the legal requirements set out in the biological agents provisions of COSHH, with particular attention to how these requirements influence design, contruction and operation of laboratories. This guidance replaces that given in ACDP Categorization of biological agents according to hazard and categories of containment and supplements that given in Working safely with research animals: Management of infection risks.