Testing Lead Chromate Paint
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Background:

Lead chromate is not often found in interior or exterior household paints. However, marine and industrial paints can contain lead chromate pigments. Paints containing lead chromate pigments include colors that are bright yellow, red, orange and some greens. Paints that are pastel or neutral in color do not contain lead chromate pigments.

LeadCheck Swabs will detect the lead in these paints but it will take longer for color to develop. In general, where lead chromate pigments are present the higher the lead chromate concentration the shorter the LeadCheck development time.

As an alternative a method is described using ChromateCheck Swabs. If no chromate is found when the surface is tested using ChromateCheck Swabs, then LeadCheck Swab test results should be instant.

Method:

Use LeadCheck Swabs: Follow the general directions for testing a painted surface.
  1. Cut a "notch" in the paint down to the substrate.
  2. Activate a LeadCheck Swab according to the directions supplied with the kit.
  3. Rub Swab tip on the test surface for about 30 seconds.
  4. If the Swab tip does not turn pink, and a lead chromate pigment is suspected:
    1. Squeeze a drop of fluid from the swab onto one of the dots on the Test Confirmation Card. DO NOT LET THE SWAB TIP TOUCH THE CARD!
    2. If the drop of fluid turns the dot on the confirmation card pink, seal the swab in a zip-lock plastic bag for further observation.
  5. Observe the tip of the swab and/or surface tested. If a lead chromate pigment is present, pink will appear on the test surface or swab tip in as few as 5 to 10 minutes, or as long as 18 hours depending on the lead chromate concentration in the paint.

Use ChromateCheck Swabs: Confirm the presence of chromate ion with ChromateCheck.
  1. Prepare a second notch on the painted surface as described in the instructions.
  2. Activate a ChromateCheck Swab according to the directions and rub the swab into the prepared notch for 30 seconds. A pink to purple color indicates the presence of chromate pigments.
Interpretation:

  1. A positive result with ChromateCheck indicates chromate pigments are present. LeadCheck development time will be longer.
  2. A delayed positive result with LeadCheck Swabs indicates lead chromate pigments are present.
  3. A positive ChromateCheck result with a negative LeadCheck result indicates that chromate pigments other than lead chromate pigments are present. Other chromate pigments such as zinc or copper chromate are not hazardous.