 chapter summary healthcare associated infections hais and outbreaks can be caused by use of contaminated medical products these medical products include devices also known as instruments or equipment and drugs also known as medications as well as biological products nutrition products and patient care items the general principles outlined in the corha principles and practices can be employed when responding to events related to medical product contamination these investigations often involve infection control assessments and require the active coordination of investigation partners across multiple jurisdictions in supplement a medical product investigations we address some unique challenges associated with identifying and responding to outbreaks related to contamination events this supplement contains information on intrinsic contamination which occurs before a medical product arrives at its point of use in a healthcare facility extrinsic contamination which results from errors made during a medical products storage preparation and use in a healthcare facility advice on recognizing and evaluating possible causes of product related transmission relative to clinical illness and other factors investigation procedures for outbreaks that potentially involve drugs and devices with an emphasis on intrinsic product contamination additional keys to success related to medical product investigations 