What Level of Lead in Paint Is Dangerous?

When Numbers Lie — And When They Don't

You've gotten lead test results and you see numbers. What do they mean? How much lead is "too much"? Is your home safe or dangerous?

Here's the honest answer, and it's more nuanced than "above X is bad, below X is fine." In my nursing training, we learned that the relationship between a lab value and a clinical outcome is rarely a simple on/off switch. Blood pressure of 140/90 isn't magically dangerous while 138/88 is fine — they're points on a continuum of increasing risk. Lead works the same way.

The regulatory thresholds I'm about to show you define "lead-based paint" for legal and compliance purposes. They tell you when disclosure is required, when RRP rules apply, and when the government considers a surface hazardous. What they don't tell you is that everything below the threshold is safe — because for children, the honest answer is that no level of lead exposure has been proven safe.

The Regulatory Definition — Where the Line Is

The federal government defines lead-based paint as paint containing lead at or above these levels:

• 1.0 mg/cm² — When measured by XRF (milligrams per square centimeter)
• 0.5% by weight — When measured by laboratory analysis (5,000 parts per million)

Paint meeting or exceeding these thresholds triggers disclosure requirements, RRP Rule compliance, and other regulatory obligations. Below these thresholds, the paint is technically "not lead-based paint" — a phrase that is legally precise and medically misleading.

What Your Test Results Actually Mean

XRF Readings (mg/cm²)

When I hand you an XRF report, here's what the numbers tell you:

• Positive (≥ 1.0 mg/cm²): Lead-based paint is present. This surface has regulatory implications — disclosure if selling, RRP compliance if renovating, and monitoring if you have young children
• Negative (below 1.0 mg/cm²): Not classified as lead-based paint for regulatory purposes. But "not regulatory" and "not present" are different things. A reading of 0.8 mg/cm² still contains lead — it's just below the legal threshold
• Inconclusive (near the threshold): XRF readings near 1.0 mg/cm² may need lab confirmation. This is where I send a sample to the lab for definitive answer. I'd rather get a precise number than guess which side of a line you're on

Lab Results (% or ppm)

• 0.5% (5,000 ppm) or higher: Lead-based paint — same regulatory implications as above
• Below 0.5%: Not classified as lead-based paint, but lead may still be present at lower concentrations

The Complication Nobody Advertises

Here's where I put on my nursing hat, and I'm going to be straight with you because you deserve it:

The regulatory threshold tells you whether paint is "lead-based" for compliance purposes. It's a legal line drawn at a specific number because laws need specific numbers. But biology doesn't work in binary. Paint containing 0.4% lead is still lead paint — just below the regulatory cutoff. A child ingesting dust from deteriorating 0.4% lead paint is still ingesting lead.

Key clinical realities:

• Paint at 0.4% lead is not lead-based paint for regulatory purposes, but it is still paint that contains lead
• Any deteriorating paint containing lead — above or below the threshold — can create lead dust
• For children, there is no safe level of lead exposure. This isn't my opinion — it's the scientific consensus that led the CDC to progressively lower its action threshold
• The dose makes the poison, but with lead and developing brains, even small doses produce measurable effects on IQ, attention, and behavior. Unlike most toxins, there's no "background level" that the body handles without consequence

When Lead Paint Becomes a Hazard (Regardless of Concentration)

Lead paint isn't dangerous while it's intact and undisturbed — this is true at any concentration. It becomes a hazard when the exposure pathway activates:

• Deteriorating: Peeling, chipping, flaking, chalking — creating dust and chips that can be ingested
• Friction surfaces: Windows and doors where paint rubs during operation — generating invisible lead dust with every use
• Impact surfaces: Areas that get bumped, scratched, or worn — dislodging particles from paint layers
• Renovation: Sanding, scraping, cutting through painted surfaces — creating massive dust generation in an enclosed space

When lead paint breaks down, it creates lead dust. Lead dust is invisible at hazardous concentrations. It settles on floors, windowsills, and horizontal surfaces. Children, with their hand-to-mouth behavior and floor-level activities, are the most efficient accidental ingestors.

Lead Dust Standards

The EPA has set separate standards for lead dust on surfaces, and these were recently tightened:

Surface	Current Hazard Standard	Previous Standard	Why It Changed
Floors	10 μg/ft²	40 μg/ft²	Evidence of harm at lower levels
Window sills	100 μg/ft²	250 μg/ft²	Window friction creates concentrated dust

These reductions weren't arbitrary. Each one followed research demonstrating that children were being harmed at levels previously considered "safe." The previous floor standard of 40 μg/ft² was protecting the regulation, not the child. The science caught up, and the numbers moved.

Soil Lead Levels

Exterior lead paint has been depositing lead into surrounding soil since the day your home was built. EPA guidelines for soil:

• Play areas: Hazard at 400 ppm — areas where children play, especially bare soil near the foundation
• Other yard areas: Hazard at 1,200 ppm — the rest of the property

Children playing in contaminated soil near Oklahoma foundations — where decades of paint weathering has concentrated lead in the "drip line" zone — can ingest lead through normal hand-to-mouth behavior. This is the exposure pathway that gets overlooked because people focus on interior paint. Half the lead risk may literally be in your yard.

Making Decisions Based on Your Results

When I deliver test results, here's the framework I walk people through:

Above threshold (positive for lead-based paint):

• Disclosure required if selling
• RRP Rule applies to renovation work — no exceptions
• Evaluate condition — is paint intact or deteriorating? This is the critical question. Lead paint in good condition and lead paint that's flaking are entirely different risk categories
• Consider occupant risk — children under 6? Pregnant women? These populations change the urgency of your response
• Don't panic — presence of lead paint is not an emergency. Poor condition lead paint with children present is an urgency, not an emergency. You have time to act thoughtfully

Below threshold but lead detected:

• Technically not "lead-based paint" for regulatory purposes — no disclosure requirement, no mandatory RRP
• Still monitor condition and maintain painted surfaces — the lead doesn't care about the regulatory threshold
• Consider occupant sensitivity — if your 3-year-old is chewing on the windowsill, the fact that the paint is 0.4% lead instead of 0.6% lead is cold comfort

No lead detected:

• No lead-related restrictions on the tested surfaces
• Renovation can proceed without lead-safe work practices for those surfaces
• Keep the report — documentation of negative results has value, especially for future sales or renovations

Keep Reading

Is Lead Paint Dangerous If Not Peeling?

When intact paint is and isn't a hazard.

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How to Test for Lead Paint

XRF vs lab analysis vs DIY kits.

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When Was Lead Paint Banned?

The 1978 ban and Oklahoma implications.

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