INTRODUCTION WHY ARE INFECTIOUS SUBSTANCES REGULATED IN TRANSPORTATION? An infectious substance is regulated as a hazardous material under the U.S. Department of Transportation (DOT) Hazardous Materials Regulations (HMR), 49 CFR Parts 171-180. The HMR apply to any material DOT determines is capable of posing an unreasonable risk to health, safety, and property when transported in commerce. An infectious substance must conform to all...