Lead toxicity comes from inhaling lead or consuming it. Before the 1980s, when the government banned lead from consumer use, it could be found in paint, plumbing, pipes, ceramics, and even gasoline. Lead paint is toxic for the same reason lead itself is toxic, which is why lead poisoning from paint presents the same as lead poisoning from water or food sources, with a slight increase in respiratory symptoms vs. digestive symptoms. Lead paint is most dangerous when it’s old and peeling, cracking, or otherwise disturbed. This increases the concentration in the air and, therefore, in breathable air. 

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.

When a surface that contains lead dust is disturbed, the dust can float about in the air for roughly an hour before settling again. Since you cannot see the dust, it is important always to wear protective gear when working with any materials that may contain lead paint and to keep children, pets, and others away from the area for as long as possible

While not all homes built before 1978 contain lead paint, enough do, so you’ll still want to test to be on the safe side. The federal government banned lead-based paint for homes in 1978, but your state may have banned lead before that time. Around 24% of homes built between 1960 and 1977 contained lead-based paint, while 87% of homes built before 1940 contained lead-based paint.