Notice of Amendment of EPA Traceability Protocol
                                
                        August 25, 1999


This action will amend (effective immediately) EPA Traceability Protocol
for Assay and Certification of Gaseous Calibration Standards,
September 1997, EPA-600/R-97/121 to permit use of source analyzers
in addition to ambient analyzers in Procedure G2 (Section 2.3.)

Section 2.3.1 Applicability
Delete the last sentence of paragraph 1 and substitute the following:
The procedure employs either an ambient air quality level pollutant gas
analyzer or a source level analyzer to quantitatively compare diluted
gas samples of both the candidate and reference standards.

In paragraph 2 of Section 2.3.1, delete the second sentence beginning
with "Additionally, dilution allows...."

Users of this amended procedure should state in their certifications that
analysis was by amended Procedure G2 (August 25, 1999.)