EMSL Recommends XRF to Quantify Lead in Ceramic Tile

When the Environmental Protection Agency (EPA) and Consumer Products Safety Commission (CPSC) implemented rules and regulations regarding the use of lead in paints, they first had to define paint. The CPSC Office of Compliance defined paint in 16 CFR 1303 in which they published that “paint or similar surface coating materials” were terms that generally applied to liquid or semi-liquid products that change to a solid film when thinly applied to wood, stone, metal, cloth, plastic, or a similar surface. Lead-glazed ceramics are commonly made by dusting a dry mixture onto the tiles and then kiln-firing it such that it bonds to the substrate. That is why glazes are exempt from the EPA and CPSC regulations where lead is concerned.

The HUD Guidelines for the Evaluation and Control of Lead-based Paint Hazards in Housing states that unpainted ceramic tiles are not considered paint and in fact are specifically exempt from the CPSC definition. Demolishing lead-glazed tiles may still create a lead-dust hazards yet analysis of ceramic tiles using the same method as paint chips is misleading and not within the scope of the EPA/HUD program.

Ceramic Tiles and Conventional Acid Digestion: Why is this a problem?
Analysis of ceramic tiles utilizing routine preparatory methods (e.g., EPA SW 846 Method 3050B) for paint chips is problematic due to the inability of the hot acid digestion scheme to breakdown the high-fired glazing; this will lead to potentially low or false negative lead results. The instrumental analysis chosen, whether Flame Atomic Absorption (FLAA) or Inductively Coupled Plasma (ICP), will not matter as the preparation procedure is the same for both instrumental techniques. To best evaluate a ceramic tile for risk assessment purposes (informational only), it is recommended that you use X-ray fluorescence (XRF) to examine the ceramic tiles for potential lead content. Since the instrument is using x-rays, it can penetrate the glazing without the need for digestion by acid.

Note: Some handheld XRF analyzers may not be adequately configured for quantitative analysis of lead in ceramic products and glazes; refer to manufacturer’s specifications and guidelines.

Rather than using XRF, can I request that my ceramic tile be analyzed and reported as a paint chip?
Yes, but it is strongly discouraged and the report will require the following disclaimer: “Traditional lead methods are not recommended for determination of lead content in ceramic tile.”

Is analysis for Total Threshold Limit Concentration (TTLC) a suitable alternative?
No. TTLC is a State of California (22 CCR Appendix II) regulation designed to determine the presence of lead and other toxic chemicals specifically for waste characterization purposes. For determining TTLC, milling the sample to a fine dust is specifically required in the regulation. The concentration of lead found, relative to the TTLC regulation, determines if you need to proceed with additional extraction (the “WET” method) of the sample to meet the Soluble Threshold Limit Concentration (STLC) for proper disposal in a landfill. EPA SW 846 Method 3050B was designed as a preparative technique for determining environmentally-available metals, including lead on painted surfaces or surface coatings, dust and soil and is not applicable to TCLP, TTLC or STLC waste characterization procedures.

For more information, contact your Account Representative or contact EMSL’s Customer Service at 1.800.220.3675 or info@emsl.com.