Building products incorporating antimicrobial additives are becoming increasingly prevalent. Paints, and other touchable surfaces such as countertops, and virtually any product considered as an interior finish may contain one or a combination of antimicrobials. These agents are considered pesticides, but their identity—and related hazards—can be difficult for the average person to discover. This lack of transparency creates a hurdle for the informed selection of products with reduced negative impacts. No evidence yet exists to demonstrate that products intended for use in interior spaces that incorporate antimicrobial additives actually result in healthier populations. Further, antimicrobials may have negative impacts on both people and the environment. This paper, prepared by Perkins+Will in partnership with HBN, aims to present current information about reported or potential health and environmental impacts of antimicrobial substances as commonly used within the building industry, and to assist architects, designers, building owners, tenants, and contractors in understanding those impacts.