According to the Environmental Protection Agency (EPA), hazardous waste is generally classified into four main categories:

1. Characteristic Wastes: These exhibit at least one of four hazardous traits: ignitability (flammable, like gasoline), corrosivity (can rust or decompose materials, like car batteries), reactivity (unstable and can explode, like aerosol cans), or toxicity (harmful when ingested, like lead-based paint).

2. Listed Wastes: These are specific wastes from manufacturing and industrial processes that the EPA has officially designated as hazardous. They include byproducts from processes that use solvents, pesticides, and other chemicals.

3. Universal Wastes: These are commonly generated hazardous items that are subject to streamlined regulations. Examples include batteries, pesticides, mercury-containing equipment (e.g., bulbs), and some lamps.

4. Mixed Wastes: This category includes waste that contains both hazardous and radioactive components, making it subject to regulation by both the EPA and the Nuclear Regulatory Commission.

Properties should be tested for lead every 2-3 years, especially if they are older, have undergone renovations, or show deterioration of paint or interior finishes.

Lead testing in residential properties involves collecting samples from paint, dust, soil, or plumbing and analyzing them in certified laboratories to accurately identify lead levels.

If lead is detected in a property, steps should include arranging for professional removal or containment, notifying all occupants, and implementing interim safety measures to reduce exposure.