[Federal Register Volume 76, Number 15 (Monday, January 24, 2011)]
[Pages 4115-4116]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-1301]



Centers for Disease Control and Prevention

[Docket Number NIOSH-156]

Request for the Technical Review of the Draft Current 
Intelligence Bulletin (CIB): Derivation of Immediately Dangerous to 
Life and Health (IDLH) Values

AGENCY: National Institute for Occupational Safety and Health (NIOSH) 
of the Centers for Disease Control and Prevention (CDC), Department of 
Health and Human Services (HHS).

ACTION: Notice of public comment period.


SUMMARY: The National Institute for Occupational Safety and Health 
(NIOSH) of the Centers for Disease Control and Prevention (CDC) is 
conducting a public review of the draft, Current Intelligence Bulletin 
(CIB): Derivation of Immediately Dangerous to Life and Health (IDLH) 
Values. NIOSH is requesting technical review of the draft CIB. The 
draft document and instructions for submitting comments can be found at 
    Public Comment Period: Comments must be received by March 15, 2011.
    A public meeting to be convened either in Cincinnati, Ohio or via 
Teleweb may be scheduled at a date and time to be announced later if 
determined to be necessary. This public meeting will be announced via a 
subsequent notice.

ADDRESSES: Written comments, identified by docket number NIOSH-156, may 
be submitted by any of the following ways:
     Mail: NIOSH Docket Office, Robert A. Taft Laboratories, 
MS-C34, 4676 Columbia Parkway, Cincinnati, OH 45226.
     Facsimile: (513) 533-8285.
     E-mail: [email protected].
    All information received in response to this notice will be 
available for public examination and copying at the NIOSH Docket 
Office, 4676 Columbia Parkway, Room 111, Cincinnati, Ohio 45226. A 
complete electronic docket containing all comments submitted will be 
available on the NIOSH Web page at http://www.cdc.gov/niosh/docket, and 
comments will be available in writing by request. NIOSH includes all 
comments received without change in the docket, including any personal 
information provided. All electronic comments should be formatted as 
Microsoft Word. Please make reference to docket number NIOSH 156.

Laboratories, MS-C32, 4676 Columbia Parkway, Cincinnati, OH 45226, 
telephone (513) 533-8540.

SUPPLEMENTARY INFORMATION: In 1974, the National Institute for 
Occupational Safety and Health (NIOSH) and the Occupational Safety and 
Health Administration (OSHA) jointly initiated the development of 
occupational health standards consistent with Section 6(b) of the 
Occupational Safety and Health Act of 1970 for substances with then-
existing OSHA permissible exposure limits (PELs). This joint effort was 
called the Standards Completion Program (SCP). As part of the 
respirator selection process for each draft technical standard, 
Immediately Dangerous to Life and Health (IDLH) values were determined 
for each chemical. The purpose of deriving an IDLH value was to provide 
guidance on respirator selection and to establish a maximum exposure 
concentration in

[[Page 4116]]

which workers, in the event of respiratory protection failure (e.g., 
contaminant breakthrough in a cartridge respirator or stoppage of air 
flow in a supplied-air respirator), could escape safely when the 
exposure was below the IDLH value.
    Since the establishment of the original IDLH values in 1974, NIOSH 
has continued to review the available scientific data to improve the 
protocol used to derive the acute exposure guidelines, in addition to 
the chemical-specific IDLH values. This draft CIB represents the most 
recent update of the scientific rationale and process used to derive 
IDLH values based on health effects considerations determined through a 
critical assessment of the toxicology and human health effects data.
    The new process relies on a weight-of-evidence approach based on 
scientific judgment for establishing IDLH values that allows for the 
critical evaluation of the quality and consistency of the scientific 
data, and in extrapolation from the available data to the IDLH value. 
The weight-of-evidence approach refers to the critical examination of 
all the available data from diverse lines of evidence and the 
derivation of a scientific interpretation based on the collective body 
of data including its relevance, quality and reported results. 
Guidelines are presented to aid in the selection of the critical 
adverse effect, a point of departure (POD) or the point on the dose-
response curve from which dose extrapolation is initiated, and applying 
default uncertainty factors (UFs) to derive the IDLH value. 
Conceptually, the derivation process presented in this CIB is similar 
to that used in other risk assessment applications including the 
process steps of:
     Hazard characterization,
     Identification of critical adverse effects,
     Identification of a POD,
     Application of an appropriate UF based on the study and 
POD, and
     Determination of the final risk value.
    Supplemental information included within this draft CIB includes 
(1) An overview of the literature search strategy used to identify 
relevant data, (2) the scheme used to prioritize and select chemicals 
for which an IDLH value will be established and (3) an overview of the 
analysis applied by NIOSH to develop a scientifically-based approach 
for the selection of the UF during the derivation of IDLH values. In 
addition, Appendix A of the draft CIB presents an example of the 
derivation of an IDLH value for vinyl acetate (CAS 108-50-4) 
based on the new process.

    Dated: January 13, 2011.
John Howard,
Director, National Institute for Occupational Safety and Health, 
Centers for Disease Control and Prevention.
[FR Doc. 2011-1301 Filed 1-21-11; 8:45 am]