• Significant Variability Found in Toxics in Packaging Compliance Verification Testing
  • August 18, 2011 | Authors: Gregory A. Clark; Sheila A. Millar; Jean-Cyril Walker
  • Law Firm: Keller and Heckman LLP - Washington Office
  • The Toxics in Packaging Clearinghouse (TPCH)[1] released a report on July 21, 2011, that identifies significant variability in laboratory testing for total heavy metals under state "toxics in packaging" laws. The TPCH, which was formed 20 years ago to support model toxics in packaging legislation, has a states-only voting membership and an industry/public interest advisory group. As part of its ongoing effort to monitor compliance with state toxics in packaging laws,[2] the TPCH sent packaging samples to six private laboratories and one state laboratory, the California Department of Toxic Substances Control Environmental Chemistry Laboratory. Laboratories tested samples for the concentration of lead, cadmium, mercury, and hexavalent chromium, the four metals restricted by state toxics in packaging laws. All told, sixteen percent of the lead and cadmium results were deemed "unacceptable" based on variability and inaccuracy of test results. Laboratory variability in testing for heavy metals has been an important problem highlighted by manufacturers of children's products subject to limits on lead imposed by the Consumer Product Safety Improvement Act of 2008 (CPSIA).

    Each laboratory received eight packaging samples, seven of which were polyvinyl chloride (PVC), a matrix suspected to be difficult in testing. Seven of the samples contained lead and/or cadmium, with one control. A result was deemed unacceptable if the measured concentration was 25 percent above or below all of three baseline reference points. Although sixteen percent of the results were deemed unacceptable, no false positives and only one false negative occurred during the study.

    The major correctable issue identified by the TPCH was incomplete sample decomposition during sample preparation. State toxics in packaging laws set limits for total metal concentration, so the sample must be completely decomposed during sample preparation. Laboratories that perform hazardous waste or site characterization analyses are accustomed to conducting analyses for total recoverable metals, which is based on potential for environmental release, and does not require total decomposition. The TPCH recommends that when requesting analytical services, manufacturers and retailers tell the laboratory that samples must be completely decomposed prior to analysis and request confirmation of the laboratory's results. This may mean that standard analytical request forms or procedures cannot be used, and it may require additional work by the laboratory to adapt its sample preparation SOPs, but it is vital to ensuring accurate results.

    Even with improved sample preparation, however, method variability will likely remain an issue for manufacturers and retailers. False negatives and false positives were not a problem in the study, but the sample with the lowest total metal concentration had twice the legal limit. Based on the variability observed in even the well-performing laboratories, false positives and negatives would likely have occurred in significant numbers if the concentrations in the samples were close to the legal limit. Recent comments received by the Consumer Product Safety Commission (CPSC) during its assessment of the technological feasibility of the 100 ppm lead concentration limit for children's products emphasized the serious problem of inter-laboratory variability in testing for total lead alone.[3] The CPSC concluded that the available methods could be applied effectively, but did not address whether they are in fact applied effectively, and the TCPH results suggest that the problem of inter-laboratory variability may be even broader than suspected. As long as the available analytical methods and the laboratories performing them remain highly variable, companies will be forced to spend more than is necessary on compliance. Because false negatives in quality control testing (as well as false positives during compliance testing) can expose companies to liability, companies must build room for testing error into product formulations. Further, false positives can lead a company to unnecessarily discard compliant batches of material.

    The TPCH's stated purpose for the study was to raise awareness of laboratory testing issues. Despite the number of unacceptable results, the TPCH felt that overall laboratory performance was better than expected based on findings in prior studies. Nevertheless, it is clear that laboratory testing for heavy metals remains a work in progress that manufacturers, retailers and regulators must take into account.

    [1] The TPCH was created to promote the Model Toxics in Packaging Legislation developed by the Coalition of Northeastern Governors (CONEG) and to support states in their implementation of toxics in packaging laws.

    [2] Nineteen states have laws based on, or similar to, the CONEG model. These laws prohibit intentional addition of the four regulated metals and set a limit of 100 ppm total concentration of the four metals.

    [3] Section 101(a) of the Consumer Product Safety Improvement Act (CPSIA) (15 U.S.C. 1278a(a)).