Final answer:
WHMIS class D includes Poisonous and infectious material, which refers to substances harmful upon inhalation, ingestion, or skin contact and can include toxic waste that's reactive or corrosive.
Step-by-step explanation:
WHMIS class D encompasses substances that are classified as Poisonous and infectious material. These substances can have toxic effects on the body when inhaled, ingested, or upon skin contact. Toxic waste in this category might be reactive, ignitable, or corrosive, with examples including old batteries, pesticides, paint, and car oil. While oxidizing chemicals such as potassium dichromate do provide oxygen that may cause other materials to combust, and are therefore hazardous, they typically fall under a different classification within WHMIS (Class C - Oxidizing material).