InAerojet‐General Corp. v. Transport Indemnity Co.,17 Cal. 4th 38 (1997) (hereinafterAerojet),the California Supreme Court confirmed that the costs of conducting environmental investigation activities designed to avoid or at least minimize liability may be covered as defense costs under comprehensive general liability (CGL) policies and set forth certain basic parameters for insureds’ recovery of environmental investigation costs. Although the pronouncement that investigation costs “may be”; defense costs answered certain questions, the “may be”; aspects of that ruling raised additional questions, which this article seeks to answer.