CPSC Proposes to Revise Supplemental Definition of "Strong Sensitizers" Under FHSA

On February 25, 2013, the Consumer Product Safety Commission ("CPSC" or "Commission") voted to approve a Notice of Proposed Rulemaking ("NOPR")[1] to revise its supplemental definition of "strong sensitizer" under the Federal Hazardous Substances Act ("FHSA").[2] The Notice was published in the Federal Register on March 12, 2013; the deadline for comments is May 28, 2013.[3] Separately, the CPSC is issuing a "Guidance Document" that is intended to further clarify the "strong sensitizer" definition and assist manufacturers in understanding how the CPSC staff would assess whether a substance and/or product containing that substance should be considered a strong sensitizer.[4] These actions seek to bring the regulatory definition of "strong sensitizer" in line with current science, which indicates a weight-of-evidence approach to determine the strength of the sensitizer.

The FHSA requires appropriate cautionary labeling on certain hazardous household products. (Toys or other articles for children that contain certain hazardous substances are banned unless specifically exempted.) Among the hazards addressed under the FHSA are products that are toxic, corrosive, irritants, flammable, combustible, and strong sensitizers. A "strong sensitizer" is defined under the FHSA as a substance which "will cause on normal living tissue through an allergic or photodynamic process a hypersensitivity which becomes evident on reapplication of the same substance and which is designated as such" by the CPSC.[5] For a product containing a strong sensitizer to be considered a hazardous substance and to require cautionary labeling under the FHSA, the product must be capable of causing substantial personal injury or substantial illness during, or as a result of, customary or reasonably foreseeable handling or use, including reasonably foreseeable ingestion by children. This determination requires an exposure analysis that includes the route and level of exposure in the particular product, which necessarily requires a product-by-product evaluation.

In 1986, the CPSC issued a supplemental definition of strong sensitizer, set forth in 16 C.F.R. Part 1500, which clarifies how the FHSA statutory definition should be interpreted and explains the factors that CPSC will consider when determining whether a substance is a strong sensitizer. Recognizing that the science on sensitization has changed since 1986, the CPSC in 2005 convened an expert panel composed of scientists from academia, industry, and the federal government to examine the available scientific and medical information on sensitizers. The expert panel evaluated the current strong sensitizer definition in light of advances in the field of sensitization and recommended that the CPSC revise the current definition. Following the panel review, the CPSC staff developed and posted a draft technical report on the CPSC website for public, as well as scientific peer review.[6] Based on these comments, the staff developed the revised supplemental definition that is addressed by the NOPR along with the guidance document.

The NOPR would implement these recommendations by revising the definition to:

…eliminate redundancy, remove certain subjective factors, incorporate new and anticipated technology (available in the next 5 years), rank the criteria for classification of strong sensitizers in order of importance, define criteria for "severity of reaction," and indicate that a weight-of-evidence approach will be used to determine the strength of the sensitizer.[7]

The CPSC Staff is recommending that the supplemental definition take effect 30 days after publication of a final rule in the Federal Register, because the Staff believes that "the supplemental definition will not have an immediate impact on any products." In fact, the CPSC Staff believes the strong sensitizer guidance document "should assist manufacturers and other stakeholders in understanding how CPSC staff would assess whether a substance and/or product containing that substance could be considered a strong sensitizer."

I. Revisions to Supplemental Definition of "Strong Sensitizer"

    A. Definition of "Sensitizer": The CPSC proposes to revise the definition of "sensitizer" to capture those substances that sensitize through atypical mechanisms, rather than by inducing only an "immunologically-mediated response." The revised definition ensures that such sensitivity follows a "variable period of exposure" to the substance. The proposed revision also removes the provision that "occasionally, a sensitizer will induce and elicit an allergic response on first exposure by virtue of active sensitization." The purpose of the change is to eliminate concern that this sentence may be misinterpreted, such that substances that cause an irritant-only response could be erroneously included in the category of "strong sensitizers."

    B. Definition of "Significant Potential for Causing Hypersensitivity": Before designating any substance as "strong," the CPSC is proposing to require that it find that the substance has a "significant potential for causing hypersensitivity." In revising the definition of what constitutes a "significant potential for causing hypersensitivity," the Commission proposes to add qualifiers for determining susceptibility profiles, including genetics, age, gender, and atopic status, and replace the word "normal" in "susceptibility profiles in normal or allergic subjects" with "non-sensitized," to more accurately reflect what would be considered the general control population.

In determining whether a substance has exhibited a significant potential for causing hypersensitivity, the CPSC proposes to incorporate the factors that should be considered in determining whether a sensitizer is "strong" into this definition. Currently, these factors are set forth in a separate definition for "strong" under 16 C.F.R. § 1500.3(c)(5)(ii). In addition, the Commission is proposing to revise several of these factors to: (1) eliminate the quantitative or qualitative risk assessment factor; (2) rank data in order of importance; and (3) add several new factors for consideration. The Commission also proposes to make clear that a "weight-of-the-evidence approach" is to be used in determining the strength of the sensitizer because the CPSC believes there is an imprecise nature to some of the current factors and there is a potential lack of data or information available to permit useful consideration of certain factors.

    C. Definition of "Normal Living Tissue": The revisions add a specific reference to mucous membranes as a type of normal living tissue upon which a substance can cause hypersensitivity.

    D. Definition of "Severity of the Reaction": The Commission proposes to remove the definition of "severity of the reaction" and, instead, incorporate it into the factors to be considered in determining whether a substance is a "strong" sensitizer.

    E. Impact on Small Businesses: The CPSC does not believe that its revisions will require product modification or impose any additional testing or recordkeeping burdens. The obligations to label a product as a "strong sensitizer" and any costs associated with that obligation do not arise unless the Commission initiates a separate notice and comment rulemaking proceeding. The Commission does not believe that the NOPR will lead to any additional substances being designated as strong sensitizers that would not be so designated in the absence of the amendment.

II. Strong Sensitizer Guidance Document

In connection with its NOPR, the Commission is announcing the availability of a guidance document intended to clarify each section of the proposed "strong sensitizer" supplemental definition by explaining the current scientific rationale underlying the methodologies and the analysis that CPSC staff will consider when assessing whether a substance is a strong sensitizer. The Commission provides several key descriptions to better explain its revisions to the supplemental definition. These include:

• In determining what a sensitizer is, the Commission proposes to clarify that irritant-only responses are not covered. Irritant responses occur without sensitization. An irritant is any agent that is capable of producing cell damage and/or an inflammatory response in any individual if applied for sufficient time and concentration. Irritants include substances and activities such as water, detergents, solvents, acids, alkalis, adhesives and friction. Some mild irritants may require prolonged or repeated exposure before symptoms occur, while other irritants can produce an immediate reaction and may even resemble a thermal burn. By contrast, for an individual to become sensitized to a particular substance, there is a lag sensitization phase (induction), followed by a secondary immune response (elicitation phase). The amount of time and the amount of exposure (the variable period of exposure and the dose) required for sensitization will depend upon the individual, although it is generally considered that time is required for sensitization to develop.
  
  
• Determination by the CSPC that a substance poses a significant potential for causing hypersensitivity should follow a weight-of-evidence approach, using all available validated tools. The factors for consideration of hypersensitivity potential are ranked and listed in order of importance in the definition, with the FHSA preference for human data over animal data.
  
  
• The CPSC also provides a detailed discussion of test methods specific to respiratory sensitization and skin sensitization, objective criteria for evaluating the severity of a reaction in the respiratory system and on skin, and other factors it will consider.
  
  

The CPSC staff Briefing Package, including the Notice of Proposed Rulemaking and CPSC Guidance Document, is available here. The Briefing Package provides additional information on the Commission staff's interaction with other parties working on the Globally Harmonized System of Classification and Labeling of Chemicals (GHS), including its role in requesting that the LLNA test method for determination of sensitization potency, a method favored by European scientists, be referred to the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) for its review. The ICCVAM recommended that the LLNA should be used as part of a weight-of-evidence approach for potency determinations, rather than as a standalone assay, which was important in influencing other European colleagues on the OECD expert task group in agreeing to this weight of the evidence approach. The Briefing Package also discusses initiatives by the Occupational Safety and Health Administration (OSHA) to align the Hazard Communication Standard with the GHS; however, there was little discussion of differences between the FHSA and the GHS scheme that will make alignment to the GHS system challenging.

The CPSC is seeking public comment on the NOPR by May 28, 2013. CPSC staff likely will revise the draft Guidance Document based on any public comments received on the NOPR. Despite the CPSC's statement that the NOPR will not likely lead to any additional substances being designated in the absence of the amendment, only time will tell whether the supplemental definition will result in the addition of other substances to the list of strong sensitizers.

For more information on product labeling and packaging, please contact:

Sheila Millar (+1 202.434.4143, millar@khlaw.com),
Jean-Cyril Walker (+1 202.434.4181, walker@khlaw.com)