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OAR Box 1830 

Prepped by Ollie Stewart 

Document Number: 

164) IV-C-131 

Docket Number: 

A-87-11 

Printed 11/13/2008 7:21:00 AM Sheet 164 of 232 
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JZ-C-/3/ 

J.*10 S,1>-4. 

I SSI ' UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

\S /? WASHINGTON. D.C. 20460 

•"•Pfl0*t 0 

AUG 1 9 1988 

T H E ADMINISTRATOR 

Honorable John D. Dingell 

Chairman, Subcommittee on 

Oversight and Investigations 

Committee on Energy and Commerce 

House of Representatives 

Washington, DC 20515 

Dear Mr. Chairman: 

I am writing in r3Sponse to your letter of June 13, 1988 

in which you ask a number of questions pertaining to 

coordination between EPA and the National Highway Traffic 

Safety Administration (NHTSA) on a number of different motor 

vehicle-related issues. To facilitate our response to your 

concerns, these questions have been grouped into four general 

categories: (a) issues related to the memorandum of 

understanding (MOU) between EPA and NHTSA; (b) guestions 

related to an EPA contract work assignment for a comparative 

risk assessment of evaporative and refueling emission control 

components; (c) guestions related to EPA's June 30, 1988 Public 

Workshop on refueling and evaporative emission test procedures; 

and (d) NHTSA comments to EPA regarding the safety of onboard 

refueling control contained in a letter dated April 12, 1988 

from Mr. George L. Parker of NHTSA. Responses to your 

guestions in the first three areas are enclosed; responses to 

guestions in the final area will be forthcoming upon completion 

of the safety analyses required for the onboard reproposal, 

since the issues raised in Mr. Parker's comments and in your 

questions are related to these analyses. 

Thank you for your continuing interest in these matters. 

Sincerely, 

Ce® ». Thoaa. 

Lee M. Thomas 

Enclosures ,.,.> ^o^ re** * 

c c : The Honorable Charles A . Bowsner ,^\,?40V 

Comptroller General 

General Accounting Office 

T he Honorable Diane K. Steed •/;••' 

Administrator 

National Highway Traffic Safety Administration 

A • > 
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(a) Issues Related to the MOU 

EPA's Comments: We have previously sent you a copy of the MOU, 

which has been signed by Ms. Steed and myself. The MOU is now 

in effect. The MOU was published in the Federal Register on 

July 29, 1988. Also, in accordance with the MOU, 

representatives of NHTSA and EPA met on July 15 for the first 

guarterly meeting. I have been told the meeting was productive 

and discussed the status of various NHTSA and EPA rulemakings 

as well as other program issues, such as the use of Stoddard 

solvent in NHTSA vehicle crash tests and EPA's activity in the 

area of asbestos control. 

(b) Questions Pertaining to EPA's Comparative Risk Assessment 

Work Assignment 

1. Is there full accord between EPA and NHTSA regarding the 

work assignment? 

EPA initiated the work assignment at the suggestion 

of NHTSA and other safety organizations (notably IIHS and 

NTSB), and the Agency's interaction with NHTSA and NHTSA's 

review of the work assignment are fully documented in the 

public docket. Initially, EPA sent a draft copy of the 

statement of work (SOW) to NHTSA in December of 1987, 

reguesting their review and comments. NHTSA provided 

their comments in February, 1988. Their response 

consisted largely of minor editorial comments and 

technical clarifications, and these were addressed in the 

final version of the SOW. However, NHTSA added that their 

comments "should not be construed as an agreement that the 

product of the study will satisfactorily define the risks 

associated with the systems." EPA acknowledges and 

understands NHTSA's concern that the study will not 

represent the entire answer to the complex safety issue; 

it was never intended to be used as such. Nevertheless, 

the comparative risk assessment is a valuable technical 

tool which uses a standard industry practice, failure mode 

effects analysis (FWEA), for assessing risk. FMEA has 

achieved widespread acceptance because it provides useful 

results, and aside from the above reservation regarding 

the limitations of the study as a whole, NHTSA appears to 

concur that the approach specified in the SOW is 

technically correct and that the product of the work 

assignment will be useful. 
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2. What is the, timing, purpose and relevance of the 

comparative risk assessment as related to the steps 

outlined in the NPRM for analyzing and resolving the 

safety issues for all vehicles (including leadtime issues)? 

The comparative risk assessment involves a failure 

modes and effects analysis (FMEA) for ten different fuel 

system configurations. These include two base case 

systems representing the two most common current 

fuel/evaporative system approaches, four different minor 

modifications of the base systems to represent variations 

on these systems now seen in the field, and four different 

onboard system configurations. FMEA is a rigorous 

analytical technique which employs standard industry 

practice for assessing risk. The results of the 

comparative risk assessment are expected to better define 

the relative risks of various fuel system design 

parameters. EPA expects the comparative risk assessment 

to be completed in time to be fully considered in the 

deliberations regarding a final refueling control 

decision. The comparative risk assessment in no way 

considers or addresses leadtime factors. 

(c) Questions Pertaining to EPA's Evaporative and Refueling 

Test Procedure Workshop 

1. What was NHTSA's role and participation in the workshop? 

The workshop was held on June 30, 1988 to discuss 

onboard and evaporative test procedure issues. Although 

the workshop was not directed toward issues involving 

vehicle safety, NHTSA was specifically invited to attend, 

and a representative from NHTSA was among the more than 

150 attendees. A video tape of the workshop proceedings 

has been sent to the Public Docket and the EPA workshop 

handouts are enclosed in this response. 

2. Why is EPA's proposed test procedure inadequate for 

non-integrated systems? 

In its proposal, EPA indicated its expectation that 

refueling control system designs used by manufacturers 

would be integrated with current evaporative control 

functions and use a single canister system to collect both 

evaporative, and refueling losses. The alternative to such 

integrated systems would be non-integrated systems, which 

add refueling control hardware as a largely or completely 

separate system from the current evaporative controls. 
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Because of advantages such as simplicity and lower overall 

cost, EPA believed integrated systems would be the 

preferred approach, and focused most of its efforts for 

test procedure development on such systems. In 

particular, the Agency believed that integrated systems 

had the potential to deal with many of the excess 

evaporative emission problems which limit the in-use 

effectiveness of current evaporative controls. Therefore, 

although some test procedure changes were proposed to deal 

with improving the performance of current evaporative 

controls in the absence of refueling control, EPA was 

relying most directly on integrated onboard system designs 

to also address excess evaporative emissions. 

Contrary to EPA's expectations, most manufacturers 

commenting on the proposal indicated that they expected to 

use non-integrated onboard systems. A dominant reason for 

this choice was the proposed refueling test procedure, 

which manufacturers believed favored non-integrated over 

integrated systems due primarily to purge requirements. 

In analyzing these comments, the Agency concluded 

that there was a need to reexamine the proposed test 

procedures for non-integrated refueling controls, as well 

as the test procedure changes anticipated for conventional 

evaporative systems in the absence of refueling controls. 

As indicated in both the onboard and fuel volatility 

control proposals, EPA believes that insuring the control 

of excess evaporative emissions is an important aspect of 

these two actions. Thus, if non-integrated systems are 

going to be used, EPA desires to adjust its proposed test 

procedures to insure that these systems have the capacity 

to control excess evaporative emissions to a similar 

degree as would integrated systems. 

3. Why did EPA propose a test procedure that would in effect 

force one design on the foreign and domestic manufacturers? 

It was and is not EPA's intent to force any 

particular system design on the manufacturers. EPA's 

desire was to insure that essentially any design selected 

by the manufacturers would provide comparable in-use 

control performance. In suggesting an alternative test 

procedure, EPA w-as attempting to address the issue of 

in-use control of the excess evaporative emissions from 

non-integrated systems described above. Manufacturers 

remain free to choose a non-integrated control system, if 

it has sufficient capacity in the evaporative portion of 

the system to capture these excess evaporative emissions. 
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EPA believes, however, that for reasons of cost and design 

simplicity, integrated systems will most likely be 

preferred. The suggested test procedure revisions 

presented at the workshop would assure that either system 

has similar capacity to control excess evaporative 

emissions. 

4. Why did EPA assume that manufacturers would choose an 

integrated system for all vehicle lines covered by the 

proposal (since it is a performance standard that was 

proposed)? 

EPA assumed most manufacturers would choose 

integrated systems because such systems would in general 

be the simplest to engineer, and be less costly in terms 

of engineering/testing resources, hardware requirements 

and packaging. It was only after a review of the comments 

on the NPRM that the Agency determined that manufacturers 

were indicating a preference for non-integrated systems, 

in part because the proposed test procedure appeared to be 

less difficult for non-integrated, as compared to 

integrated, designs. As a result, EPA developed the test 

procedure changes presented at the workshop to ensure that 

non-integrated systems would provide eguivalent in-use 

control of excess evaporative emissions. 

5. Will the workshop cover both oil and motor vehicle 

industry issues simultaneously? 

The main focus of the workshop was on test procedure 

issues, which are primarily of interest to motor vehicle 

manufacturers. Although it was expected that the oil 

industry would have somewhat less interest in such issues, 

attendance by petroleum industry representatives was 

substantial. There was some discussion of the effect of 

volatility levels on emissions, which is of interest to 

the oil industry as well as to the automotive industry, 

but in general oil company issues were not central to the 

primary purpose of the workshop. 

6. Will tne workshop examine safety and certification issues 

regarding volatility levels (including the effects of 

ethanol on volatility)? 

Although there was some discussion of the effect of 

volatility levels on emissions, which is a certification 

issue, the purpose of the workshop was to discuss test 

procedures. Certification and safety issues specific to 
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7. 

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_ t *ra, h*»ina addressed in the 

fuei volatility u ?

ontro 1 »r.e

cknoVledqe8 th^ in-use RVP 

volatility rulemaking. ^PA acknowledges « ^ Rv p 

levels impact onboard Resigns. However, ^ ^ ^ 

levels is not an issue spe ci ide d upo n as a 

rulemaking. ^*TM.*TMl"llnq'"ill apply to vehicles result of the volatility rulemaking win <*vvi 

with onboard controls. 

-com a timing standpoint, how does the ^^P" 1 ^.*^ ? 

the steps outlined in the NPRM for resolving safety issues? 

if EPA proposes changes to the proposed test 

onboard safety reproposal. Thus, it is 

add any delay to the rulemaking schedule.