Environmental Hazards in Real Estate: Lead, Asbestos, Radon & Mold

Environmental hazards are a significant topic on the real estate licensing exam, appearing in both the national portion (under land use controls and disclosure requirements) and the state portion (where state-specific disclosure laws apply). You need to know the major hazards, the federal disclosure requirements, and the agent's responsibilities when hazards are discovered. This guide covers the four most commonly tested hazards plus key environmental laws.

Lead-Based Paint

Lead-based paint is the most heavily tested environmental hazard on the exam because it has the most specific federal disclosure requirements. Lead paint was commonly used in homes before it was banned for residential use in 1978. When ingested or inhaled (as dust), lead causes serious health problems, particularly in children — developmental delays, learning disabilities, and neurological damage.

Federal Disclosure Requirements (Residential Lead-Based Paint Hazard Reduction Act of 1992 — Title X)

For any home built before 1978, sellers and landlords must:

• Provide the buyer or tenant with an EPA-approved lead hazard information pamphlet ("Protect Your Family from Lead in Your Home").
• Disclose any known lead-based paint or lead-based paint hazards on the property.
• Provide any records or reports concerning lead-based paint on the property.
• Include a lead warning statement in the contract or lease.
• Give the buyer a 10-day period to conduct a lead-based paint inspection or risk assessment (the buyer may waive this period in writing).
• Ensure that all parties sign the disclosure form, which must be retained for at least three years.

These requirements apply to most residential housing built before 1978, with exceptions for: housing for the elderly or disabled (unless a child under 6 resides there), zero-bedroom dwellings (studios, dormitories), short-term leases of 100 days or less, and foreclosure sales. The exam frequently tests these exceptions.

Asbestos

Asbestos is a mineral fiber used extensively in building materials from the 1930s through the 1970s for insulation, fireproofing, and soundproofing. Common locations: pipe and boiler insulation, ceiling tiles, floor tiles, roofing materials, and textured paint. When asbestos-containing materials are disturbed (during renovation or demolition), fibers become airborne and can be inhaled, causing lung disease, asbestosis, and mesothelioma.

There is no federal requirement to disclose asbestos in residential transactions (unlike lead paint), but many states require disclosure of known environmental hazards, and agents have a general duty to disclose known material defects. The exam focuses on: where asbestos is commonly found, that it's dangerous when friable (crumbling and releasing fibers), and that removal must be performed by licensed abatement professionals.

Radon

Radon is a colorless, odorless, radioactive gas that results from the natural decay of uranium in soil and rock. It enters homes through cracks in foundations, gaps around pipes, and other openings. Radon is the second leading cause of lung cancer in the United States (after smoking). The EPA estimates that nearly 1 in 15 homes has elevated radon levels.

There is no federal radon disclosure requirement, but many states require radon disclosure or testing in real estate transactions. The EPA recommends mitigation for homes with radon levels at or above 4 picocuries per liter (pCi/L). Mitigation typically involves installing a vent pipe system and fan to pull radon from beneath the house and vent it outside. The exam may test the 4 pCi/L action level and the fact that radon is a naturally occurring gas, not a man-made contaminant.

Mold

Mold is a fungal growth that thrives in moist environments. While mold is naturally present everywhere, excessive indoor mold growth can cause allergic reactions, respiratory problems, and other health issues. Mold has become a major concern in real estate due to high-profile litigation and increased awareness.

There is no federal mold disclosure law, but many states have enacted mold disclosure requirements. The exam focuses on: mold requires moisture to grow (so water intrusion, leaks, and high humidity are the root causes), mold is not always visible (it can grow inside walls), and remediation involves fixing the moisture problem first, then removing affected materials. Agents should recommend professional mold inspection and remediation rather than attempting to assess or remediate mold themselves.

Other Environmental Hazards

• Underground Storage Tanks (USTs): Tanks used to store petroleum products or hazardous substances. Leaking USTs can contaminate soil and groundwater. Federal law requires registration, leak detection, and proper closure of USTs. The exam may test that USTs are a significant concern for commercial properties and former gas station sites.
• Carbon Monoxide (CO): An odorless, colorless gas produced by incomplete combustion of fuels. CO detectors are required in many states for residential properties. Not a "site contamination" issue but a safety hazard tested on some state exams.
• Polychlorinated Biphenyls (PCBs): Toxic chemicals formerly used in electrical equipment and building materials. Found in older fluorescent light ballasts and caulking. Regulated under the Toxic Substances Control Act.
• Wetlands: Not a health hazard, but an environmental land use restriction. Development in wetlands is restricted under the Clean Water Act and may require permits from the Army Corps of Engineers.

Key Environmental Laws for the Exam

• CERCLA (Comprehensive Environmental Response, Compensation, and Liability Act — "Superfund"): Establishes liability for the cleanup of hazardous waste sites. Key exam point: CERCLA imposes strict, joint and several, and retroactive liability on potentially responsible parties (PRPs), including current owners, past owners at the time of disposal, generators of hazardous substances, and transporters. This means a current property owner can be liable for cleanup costs even if they didn't cause the contamination — a critical risk for real estate buyers.
• RCRA (Resource Conservation and Recovery Act): Governs the management of hazardous waste from "cradle to grave" — generation, transportation, treatment, storage, and disposal.
• Clean Water Act: Regulates discharges into navigable waters and protects wetlands. Section 404 permits are required for dredging or filling wetlands.
• Residential Lead-Based Paint Hazard Reduction Act (Title X): The federal lead disclosure law described above.

The Agent's Role: Disclosure and Due Diligence

Agents are not expected to be environmental experts, but they have important responsibilities:

• Disclose known hazards: If you know about lead paint, asbestos, a leaking UST, or any other environmental hazard, you must disclose it. Failure to disclose known material defects is both a legal and ethical violation.
• Recommend inspections: You should advise buyers to conduct appropriate environmental inspections, especially for older properties. For pre-1978 homes, you must facilitate the lead paint disclosure process.
• Don't give expert opinions: If a buyer asks "is this mold dangerous?", the correct answer is "I'm not qualified to assess that — you should consult a certified mold inspector." Agents who offer environmental opinions beyond their expertise create liability for themselves and their brokers.
• Document everything: Keep copies of all disclosure forms, inspection reports, and written communications about environmental issues.