The National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention (NIOSH, CDC) is conducting a peer review of the NIOSH document entitled Current Intelligence Bulletin: Evaluation of Health Hazard and Recommendations for Occupational Exposure to Titanium Dioxide. This document has been determined by NIOSH to be a Highly Influential Scientific Assessment according to Office of Management and Budget (OMB) guidelines under the Federal Data Quality Act 2000 (Public Law 106-554, Section 1(a)(3)[515]). The overall goal of the peer review is to enhance the quality and credibility of Agency recommendations by ensuring that the scientific and technical work underlying these recommendations receives appropriate review by independent scientific and technical experts. The peer review charge was developed in accordance with OMB guidelines, is consistent with NIOSH peer review practice, and is meant to ensure that credible and appropriate science is used in the development of its worker protection recommendations for titanium dioxide exposure in the workplace.

Charge to the Peer Reviewers

The goals of this document are to (1) describe the relevant animal, human and in vitro studies on the health effects of titanium dioxide (TiO₂), (2) provide a quantitative risk assessment based on dose-response information from the rat and human lung dosimetry modeling, and (3) describe the rationale NIOSH used in the development of the draft recommended exposure limits (RELs). The charge to the Peer Reviewers is to objectively review the document to determine whether

• the hazard identification is a reasonable reflection of the available scientific studies,
  
  
• the risk assessment and dosimetric modeling represents a reasonable methodology for estimating worker risks from exposure to TiO₂, and
  
  
• the data and analysis used by NIOSH were appropriate for the scientific conclusions that formed the basis of the proposed RELs.

To facilitate review of this Current Intelligence Bulletin, the five questions below should be considered:

1. Is the hazard identification and discussion of health effects for TiO₂ a full and reasonable reflection of the human and animal studies in the scientific literature?
   
   
2. Are the risk assessment and dosimetric modeling methods used in this document appropriate and relevant?
   
   
3. Are the sampling and analysis methods adequate to characterize worker exposure to fine and ultrafine TiO₂?
   
   
4. Is the use of particle surface area as a dose metric appropriate for estimating worker risks from inhalation of TiO₂?
   
   
5. Are there additional relevant studies or methods that NIOSH should consider in developing its RELs for TiO₂?

The Peer Reviewers will be provided all substantive public comments received in the NIOSH Docket Office by March 31, 2006. Upon request, NIOSH will provide the Peer Reviewers with any statistical model not described in the appendices to the document.

Public Meeting
A public meeting will be held on February 27, 2006, from 9 a.m. to 4 p.m. at the Robert A. Taft Laboratory in Cincinnati, Ohio, as a forum for scientists and representatives of government agencies, industry, labor, and other stakeholders to discuss the document. The meeting will be open to the public, limited only by the space available.

Time Frame for Review
We request that peer review comments be submitted to the NIOSH Docket Office by April 30, 2006. Please return your written comments either by mail (to Diane Miller, NIOSH Docket Office, Robert A. Taft Laboratories, Mail Stop C-34, 4676 Columbia Parkway, Cincinnati, Ohio 45226) or electronically via e-mail (to nioshdocket@cdc.gov.) All electronic comments should be formatted as Microsoft Word. Please make reference to docket number NIOSH-033.

List of Reviewers

• Chao W. Chen, Ph.D.
  Senior Statistician
  National Center of Environmental Assessment
  U.S. Environmental Protection Agency
  
  
• Mr. Harvey Clewell
  Director, Center for Human Health Assessment
  Centers for Health Research
  Chemical Industry Institute for Toxicology (CIIT)
  
  
• Prof. Dr. med. Helmut Greim
  Institute of Toxicology and Environmental Hygiene
  Technical University of Munich
  
  
• Franklin E. Mirer, Ph.D., CIH
  Director, Health and Safety Department
  International Union - UAW
  
  
• Jonathan M. Samet, MD, MS
  Chairman, Department of Epidemiology
  Bloomberg School of Public Health
  Johns Hopkins University