SCOTT-MARRIN, INC.

6531 BOX SPRINGS BLVD. • RIVERSIDE, CA 92507-0725

PHONE (951)653-6780 • FAX (951)653-2430 • jack@scottmarrin.com

January 30, 2005

Robert Wright,

Air Pollution Prevention and Control Division

US Environmental Protection Agency

Research Triangle Park, NC 27711

wright.bob@epa.gov

References:

1) “Request for Suggestions for Revisions to EPA Traceability Protocol for Gaseous Calibration 

Standards”, Robert S. Wright, email dated December 23, 2004.

2) “EPA Traceability Protocol for Assay and Certification of Gaseous Calibration Standards”, Report 

Number EPA-600/R-97/121 dated September 1997

3) http://www.epa.gov/airmarkets/monitoring/calgasauditfailureratebyreferencestandard.xls

Dear Bob,

Thank you for the opportunity to respond to your Request for Suggestions for Revisions to the EPA 

Traceability Protocol (Ref 1). Our company, Scott-Marrin, Inc. has been producing gas mixtures since 

1974. Our mixtures have been audited by EPA beginning in the late 1970s and we have been producing 

EPA Protocol mixtures since the middle 1980s when the first EPA protocol documents were published. 

We are a small company competing against very large companies and the majority of our business is 

producing EPA protocol mixtures.

My first comment addresses your proposal to revive the audit program by contracting with NIST to 

perform the audits with the costs of this audit program being borne by the EPA Protocol Gas producers 

themselves. This is a departure from all previous audits where the audits were performed by third party 

contractors presumably selected on a competitive bid basis and the costs were provided through the 

budget of the USEPA. I have two problems with your proposed approach.

First, although NIST is qualified to provide accurate analyses of gas mixtures, their prices to provide 

analytical services and program management are sure to be much higher than qualified private sector 

companies presumably contracted on a competitive bid basis. Although I have no first hand knowledge of 

what EPA was paying for the previous EPA Protocol Gas audits, I am very familiar with the prices of NIST 

SRMs and the price to have NIST periodically recertify these SRMs when they expire. We consider NIST 

pricing to be very expensive, but necessary to achieve accurate SRM gas standards traceable to NIST. I 

believe that it would be much more suitable for NIST to be the auditor of a competitively selected private 

sector Protocol Gas auditor. In any case, a reliable, independent audit of the work of any EPA Protocol 

Gas auditor, including NIST, should be a requirement.

Second, since our company is a producer of EPA Protocol Gas mixtures, it is proposed that we directly 

pay for the audit services. I am concerned about the equity and affordability of this new approach. This is 

especially true since our company is one of the smallest companies currently manufacturing and selling 
our own EPA Protocol Gas mixtures. Our manufacturing competitors have an annual gross income which 

is 20 to 1000 times our annual gross income. I am very concerned about a small company such as ours 

being required to pay a currently unknown large amount of money relative to our net income to participate 

in the audit program compared to the small amount relative to the net income of the large specialty gas 

companies. The relative sizes of our competitors would unfairly penalize small companies such as ours if 

this audit proposal is adopted. Since Congress has presumably seen fit to inadequately fund EPA for this 

activity, I am suggesting that alternate funding sources, such as the much larger user community who are 

currently regulated by EPA and who benefit from using EPA Protocol Gases, be sought to pay for the 

audit function. The audit program costs spread over a much larger population will not burden any small 

group.

In general, I consider the EPA Protocol-97 document (Ref 2) to be an excellent guide to producing quality 

gas mixtures which doesn’t need a lot of modifications. I also believe that the use of performance 

specifications in the present EPA Protocol document is the best approach, while leaving the exact details 

of how to specifically meet the performance specifications up to the individual gas manufacturers.

Regarding the list of informal suggestions which you have supplied, I have the following comments:

-include a procedure specifically for the use of Fourier Transform Infrared Spectroscopy;

Comment: Does this suggestion imply that EPA is going to include a recommended list of 

analyzers or methods to be used to analyze EPA Protocol Gases? Or is this instrument being singled out 

for inclusion in the Protocol document because of its inherent operational complexity? If this is the case, 

then standardized operating procedures should be included in the Protocol document.

- improve statistical procedures for uncertainty calculations and revise the Excel spreadsheet;

Comment: The EPA Protocol-97 statistical procedures for uncertainty calculations are very 

sophisticated and although I am not a statistician nor do I have a statistician on my staff, the calculations 

have always appeared to be inappropriate when considering the very limited number data points, namely 

3, which they are being applied to. In their defense, the EPA Protocol-97 calculations give a desirable 

result and they are useful in finding problems, however, whether they truly represent the accuracy of the 

analyses is questionable. Perhaps this is why you are considering a change in the calculations?

- include mercury calibration standards in the protocol;

Comment: We don’t have any experience with these standards; however, if there is a need, they 

might as well be included.

- eliminate (or retain) gas manufacturers intermediate standards (GMISs);

Comment: The elimination of the use of the GMIS is the MOST TROUBLING SUGGESTION on 

your list. As shown on your summary spreadsheet of the most recent EPA Protocol Gas audit (Ref 3.), 

the use of a GMIS does not result in failures of mixtures to meet the EPA accuracy specifications. In fact, 

one might conclude from your spreadsheet that the use of SRMs and NTRMs leads to higher failure rates. 

I’m not suggesting this is an accurate interpretation; however, it certainly is an accurate interpretation that 

the GMIS is NOT an impediment to achieving accurate analyses. In addition, my review of past EPA gas 

audits dating back to the early 1980s shows that our company, Scott-Marrin, Inc. is one of the only if not 

the only manufacturer that has provided gases which have all had an accuracy of better than the EPA 2% 

specification. Since we have always used the GMIS or its predecessors as intercomparison standards 

when performing our EPA Protocol analyses, our accuracy achievement is due to our focus on using 

accurately analyzed GMIS reference standards and carefully following the published EPA procedures.

In addition, eliminating the use of the GMIS would require the use of either an SRM or an NTRM. Since 

the SRMs contain too small a volume of gas to use as daily intercomparison standards, the NTRMs will 

be the sole reference standards to use for EPA Protocol Gas production. Our company is too small to 

produce NTRMs; therefore, we would be forced to purchase very expensive NTRMs from our 
competitors. This assumes, of course, that ALL NTRMs are available for purchase any time they are 

required. This availability is nowhere near guaranteed and based on past experience is probably not 

going to happen. A review of the internet sites and catalogs of all known producers of NTRMs shows no 

listing of available NTRM products, let alone prices for these products. A recent telephone conversation 

with a large producer of NTRMs confirmed the lack of a guaranteed availability for commercial customers 

of these products. In addition, the availability of every NTRM as a companion to an existing SRM is also 

not assured. Since the use of the GMIS does not pose a technical problem as evidenced by your recent 

audit data, I am very suspicious that the elimination of the GMIS is a suggestion by one or more of the 

NTRM producers to achieve a competitive advantage over other manufacturers. One final point; even 

though NTRMs are declared to be equivalent to SRMs, they are to my knowledge, secondary to SRMs. 

The GMIS, if it is compared directly to an SRM, is also secondary to an SRM. As a point of information, 

our company performs additional work on the GMISs which we produce. For example, we initially 

analyze each GMIS 4 or more times over a 3 month period and we analyze each GMIS every year rather 

the required 2 years. We feel these additional analyses increase the accuracy and reliability of the GMIS 

and, by the way, the annual analyses exceed the analysis requirements of NTRMs. Please do not 

eliminate the GMIS.

- lengthen the certification periods for EPA Protocol Gases;

Comment: These comments are the result of our experience performing EPA Protocol Gas 

recertifications over many years. They also err on the conservative side. I apologize for not having 

supporting documentation to submit.

a) The recertification interval for CH4, O2, CO2, and C3H8 can certainly be greater than 3 years. 

Although these gas mixtures are usually used up in 3 years, these mixtures will certainly be stable for 4 to 

6 years and probably much longer.

b) A 36 month interval for CO from 8 to 50 ppm seems to be a prudent. We have never seen CO change 

at higher concentrations in aluminum cylinders, so 4-6 years is acceptable above some threshold around 

20 to 50 ppm.

c) The 4 ppm Nitric Oxide concentration range for 24 months specified in the EPA Protocol-97 document 

is too low a threshold. The lower threshold for Nitric Oxide mixtures should be more like 20 ppm to 

warrant a 24 month recertification interval. For concentrations in the range of 4 to 20 ppm, a range of 12 

months would be more appropriate. For less than 4 ppm Nitric Oxide, a 6 month initial interval followed 

by a 12 month interval if successfully demonstrating concentration stability seems appropriate.

d) The current intervals of 40 to 499 ppm SO2@ 24 months and 500 ppm SO2 @ 36 months should 

remain unchanged.

e) The current interval of 4+ ppm H2S@ 12 months should remain unchanged. If higher concentration 

H2S SRMs are made available then a 24 month interval should be considered for concentrations 

exceeding 50 to 100 ppm.

- change the cylinder pressure limitations for EPA Protocol Gases;

Comment: The current recertification pressure limit of 500 psig is about right. Below this 

concentration, the recertification is not cost effective anyway. The minimum use pressure limit of 150 psig 

could be lowered to 100 psig without problem. Most gas mixtures in aluminum cylinders are going to be 

stable to less than 25 psig, however, some ‘reactive’ gas mixtures may not be.

- include a procedure for analyzing and certifying zero gases;

Comment: This would be very desirable. Several different standardized grades should be 

specified to include the range of EPA Protocol Gas applications.

- include gas dilution systems in the protocol;

Comment: This too would be very desirable. Performance specifications and calibration 

standards and methods are required.

- tighten documentation requirements;
Comment: I have no idea what this is referring to. The documentation requirements specified in 

the EPA Protocol-97 Gas document seem appropriate and complete.

- develop audit participant identification number for regulatory data reporting purposes;

Comment: OK, if this really has a useful purpose.

- require ISO 17025 accreditation for producers of environmental calibration gases;

Comment: We are not currently ISO certified nor do we have any expertise with ISO certification. 

However, in looking into the ISO 17025 accreditation standard, it would seem to duplicate some of the 

existing EPA Protocol-97 Gas document requirements. I believe the EPA Protocol Gas document is a 

sufficient controlling standard that can be used to achieve the goal of producing accurate EPA Protocol 

Gas standards. Therefore, I don’t think it is necessary or desirable to be ISO 17025 accredited to achieve 

the EPA Protocol Gas program goals. I also don’t think it should be required, since it would be costly and 

favor large companies. 

- include provision for preparation and analysis of batches of EPA Protocol Gases;

Comment: To my knowledge there is no provision against preparing EPA Protocol Gases in 

batches. Therefore, in the absence of specifics, this suggestion implies that a procedure for the batch 

analysis of EPA Protocol Gases be considered. This would seem to defeat the main tenet of EPA 

Protocol Gases, namely that of maintaining quality by individually certifying each and every mixture to 

eliminate errors.

- require on-site visits of specialty gas producers by EPA representatives;

Comment: OK. My only objection would be the cost to perform this level of audit. Perhaps this 

should be considered for those specialty gas producers who fail an audit.

- provide for technical assistance/outreach to specialty gas producers by NIST representatives;

Comment: Isn’t his already available?

I only have one additional recommendation. NIST should be encouraged to produce the following 

additional SRMs to support the EPA Protocol Gas program. 50 and 100 ppm Hydrogen Sulfide in 

Nitrogen, 250 ppm Sulfur Dioxide in Nitrogen, 5 ppm Carbon Monoxide in Air, and 50, 100 and 1000 ppm 

Methane in Air or Nitrogen are not currently available and their availability would improve the EPA 

Protocol Gas program.

The fact that I am not submitting many additional suggestions is only an indication that I think the EPA 

Protocol-97 Gas document in its present form is very good and could only be a little better with some 

additions and a little tweaking. In summary, the unspecified costs of your audit proposals and the 

elimination of the GMIS are very bad ideas which I feel would seriously impact our ability to produce EPA 

Protocol Gases and thereby threaten the existence of our company.

Please feel free to discuss any of the above comments with me. I can be contacted by phone at 951-653-

6780 or by email at jack@ scottmarrin.com.

Best regards,

Jack Marrin

President