Editors' Summary: The federal government has broad authority to protect the public health and the environment from hazardous substance pollution, but that power often must sit idle until the nature of the hazard posed by a given disposal site can be determined. EPA can investigate apparently hazardous disposal sites itself, for example under §104(b) of CERCLA. The Agency also orders private parties to conduct preliminary investigations of sites. Under RCRA §7003 and CERCLA §106(a) EPA orders monitoring of sites believed to present imminent and substantial endangerment to public health or the environment. The broadest authority to order monitoring of hazardous waste sites is found in RCRA §3013; authority that EPA has used in an increasing number of cases in recent years. In this Article, Ms. Smith, who has negotiated a number of §3013 orders, examines the bounds of EPA's authority under the section and offers practical suggestions for the recipient of §3013 orders.