- The outbreak is occurring in the context of a dynamic marketplace for e-cigarette, or vaping, products, which may have a mix of ingredients, complex packaging and supply chains, and include potentially illicit substances.
- Users may not know what is in their e-cigarette or e-liquid solutions. Many of the products and substances can be modified by suppliers or users. They can be obtained from stores, online retailers, informal sources (e.g. friends, family members), or "off the street."