Today's highly litigious world demands that providers of mold remediation services are able to protect themselves in the event of a lawsuit. By adhering to approved industry standards, contractors can protect their business and themselves.Remediators and other parties to the remediation process often request specific guidance regarding action levels that trigger remediation activities or confirm remediation success. Quantifying visible levels of mold growth alone are not feasible as an action level decision criterion, because of the wide range of occupant susceptibility and the imprecise measurement of exposure, along with insufficient science to support conclusions in this area as yet.Thus, S520 provides a philosophical shift away from setting numerical mold contamination action levels. Instead, it establishes mold contamination definitions, descriptions and conditions, and general guidance, which, when properly applied, can assist remediators and others in determining criteria that trigger remediation activities or confirm remediation success.This standard was written over the course of some four years with the assistance of 35 professionals on the S520 standard development committee, with an additional 60-70 serving on various subcommittees. The first draft was sent out to some 350 industry professionals during the peer review process. The editing committee received back 827 comments, all of which were cataloged, read, and evaluated, and either incorporated into the document, excludedrecorded the reason for exclusion. Legal review has been accomplished by four lawyers (including lawyers who represent both plaintiffs and defendants).