Final answer:
Under WHMIS, a 'fugitive emission' is defined as an Escaping Hazardous Substance, representing a release of a hazardous substance into the environment, often inadvertently.
Step-by-step explanation:
Under WHMIS (Workplace Hazardous Materials Information System), a "fugitive emission" refers to a leaking or escaping hazardous substance. Therefore, the correct answer is B. Escaping Hazardous Substance. Fugitive emissions occur when a hazardous substance is released into the environment during processes, storage, or handling, often inadvertently. Such emissions can pose significant risks to human health and the environment and must be controlled under proper hazardous waste management protocols detailed by the Environmental Protection Agency (EPA).