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OAR Box 1830 

Prepped by Ollie Stewart 

Document Number: 

150) IV-C-117 

Docket Number: 

A-87-11 

Printed 11/13/2008 7:20:59 AM Sheet 150 of 232 
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/ A -^ UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

VSZi y ANN ARBOR. MICHIGAN 48105 

iZ -C - 111 

^ 

UH 6 1988

 OFFICE

 OF 

O U M

 AIR AND RADIATION 

Mr. Sam Leonard 

Auto Emission Control 

Environmental Activities Staff 

General Motors Corporation 

30400 Mound Road 

Warren, MI 48090-9015 

Dear Mr. Leonard: 

We have recently received a copy of your May 6, 1988 

letter to Administrator Steed of NHTSA responding to issues 

raised by ^Mobll' about your safety testing of a prototype. 

^onboard control system designed by Mobil. While not desirir 

Ito take a position at this time on the issues raised by Mobj 

or the validity of the testing which GM has performed, w« fe< 

compelled to respond to some items in your letter 

Ms. Steed. This is necessary because we believe that your', 

letter implies that the system which you tested was one typical, 

.-of what EPA would expect to see used on production vehicles for 

Vonboard refueling control. In your letter you state that this 

^system ,was "endorsed" by EPA, and that our recent development 

'of a simplified onboard system implicitly acknowledges that the 

Mobil type of onboard system would not be acceptable from a 

safety standpoint. Given the overall context, both of these 

assertions are false. 

.« 

First of all, EPA has never "endorsed" any specific 

manufacturer's system for onboard control. We have identified 

generic types of systems which might be used, but it has always 

been clear that the serviceability of a specific system is a 

function of details of the design, materials and packaging as 

related to the particular car line on which it is to be used. 

It is this aspect of your testing of the Mobil system which is 

most troubling to us. GM failed to take any steps to adapt 

.what was an early design prototype to proper vehicle use. This 

was -in spite of your acknowledgement that Mobil described its 

system as one which should be adapted to "common automotive 

production methods and materials." If this simple step had 

been taken, one v/ouV • not have used a common paint thinner can 

for a 1 iquic-vapc-; -*~aratcr, or copper tubing connected to 

rubber hcseG vith y.-S:yyyy cl.a.'r.os

 ror -/apcr lines. Thus, the 
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crash failures which resulted from your testing would in all 

probability. not have occurred, since they resulted from these 

inadequate approaches to proper materials selection for a 

production-type system. To our knowledge, all parties to the 

safety debate over onboard controls have already agreed that a 

vehicle can readily be designed to pass crash tests such as 

those which you have conducted. 

Your statement that EPA has implicitly acknowledged that 

systems of the type chosen by Mobil are unacceptable from a 

safety standpoint is also incorrect. Our previous safety 

analyses have dealt with all known safety questions raised 

about such systems and shown that there are straightforward 

engineering solutions available. Your crash tests do not 

change that situation since such solutions were not 

incorporated into the system which you tested. 

Nor does our development of a simplified system imply that 

we consider previous systems to be unsafe. As we have clearly 

stated at all of our presentations about this hardware, it was 

developed to deal with the so-called "complexity" argument, 

advanced by GM and others, that increased complexity inherently 

implies degradation of safety. EPA does not agree with 'this 

line of argument, but chose to develop a simplified system in 

order to satisfy those parties who do. It even appears to us 

that many manufacturers do not actually accept this argument 

since, as we have noted in our presentations, the complexity of 

fuel tank venting systems has increased dramatically in recent 

years. Presumably this has been done without compromising 

safety. Incidentally, our new hardware is not a "completely 

redesigned" onboard system. Rather, it is an evolutionary 

improvement of earlier designs, and is quite similar to designs 

submitted, for example, by API in its comments on our proposal 

and most recently by Toyota at the SAE Government/Industry 

meeting. 

In your letter you mention the underhood fire 

demonstration testing which you also had done. Your letter 

seems to imply that you have satisfactorily resolved the 

questions raised by EPA with regard to this testing. This is 

not the. case. As we have noted in our correspondence to you on 

this subject, your explanations of the source of vapors for the 

underhood fire are not fully satisfactory. The vapors seem to 

be related as much to evaporative emissions as to the refueling 

operation. In follow-on testing which you had conducted at our 

request, Failure Analysis Associates demonstrated that current 

evaporative systems will create fires under the same tampering 

mode. This was demonstrated under conditions which would only 

produce minimal evaporative vapor generation rates from the 

fuel tank (vehicle idle). For other conditions, it is possible 

that more severe fires could be produced. 
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Please be advised that we are placing your letter, along 

with the accompanying opinions of Mr. Robert C. Lange of 

Failure Analysis Associates, in the public docket. They will 

both be given full consideration in our continuing evaluation 

of the onboard safety issue. 

Sincerely yours, 

,-"". o-y / 

^.yyy<-'-^- ' / 7 / 

^Charles L. Gray, Jr/ 

Director 

Emission Control Technology Division 

cc: Public Docket A-87-11 

The Honorable Diane K. Steed, NHTSA 

6054W