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OAR Box 1830 

Prepped by Ollie Stewart 

Document Number: 

173) IV-C-140 

Docket Number: 

A-87-11 

Printed 11/13/2008 7:21:00 AM Sheet 173 of 232 
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| J^Z , ? UNITED'STATES ENVIRONMENTAL PROTECTION AGENCY 

\ .<f WASHINGTON. D.C. 20450 

w

 OCT 2 7 !9Bb 

THE ADMINISTRATOR 

The Honorable John D. Dingell, Chairman 

Subcommittee on Oversight and Investigations 

Committee on Energy and Commerce 

U.S. House of Representatives 

Washington, DC 20515 

Dear Mr. Chairman: 

I am writing in response to your letters of September 15 

and October 14, 1988. First, I will respond to the questions 

in the September letter related to EPA's proposals for fuel 

volatility and onboard refueling controls. My responses are 

numbered according to your Questions. At the end of this 

letter I discuss the issues raised in your October 14 letter. 

1. The first set of ouestions concerned the National 

Highway Traffic Safety Administration's (NHTSA) review of our 

new onboard safety study and how this impacts the timing of the 

Supplemental Notice of Proposed Rulemaking (SNPRM). A draft 

SNPRM was sent to the Office of Management and Budget (OMB) for 

review on September 15, 1938, prior to receipt of NHTSA's 

comments and also prior to receipt of your letter of that day. 

We. do not feel that this action was in any way premature. We 

never intended to repropose before receiving NHTSA's analysis. 

The intent of the reproposal is to make both our reanalysis of 

tne safety issue and NHTSA's comments available for public 

review and comment and also to assess other changed 

circumstances. Therefore, we believed all non-safety portions 

of the package could be reviewed by OMB at that time. You know 

that OMB returned the package to us pending receipt of the 

NHTSA comments, an action which we believe will unnecessarily 

delay issuance of the SNPRM. As you have reauested, a copy of 

that package (draft preamble and reaulations) is included as an 

enclosure. We respectfully request that you not release these 

draft documents to outside parties. 
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2. In addition to addressing safety concerns, the SNPRM 

contains a variety of test procedure changes in response to 

comments received indicating the need to better control excess 

evaporative and running loss emissions. The changes to the 

earlier test procedures are outlined in a table at the 

beginning of the enclosed regulations. These changes and the 

reasons for them are also discussed in more detail in the 

preamble. While interested parties were sent notice of these 

revisions to the originally proposed test procedures on 

September 1, 1988, the SNPRM provides EPA a ready means to 

include these matters in the public hearing planned following 

publication of that notice. 

3. As you noted in your letter, EPA desires to apply 

the proposed evaporative test procedure changes to 

methanol-fueled vehicles as well as gasoline-fueled vehicles. 

Although EPA had proposed emissions standards and test 

procedures for methanol-fueled vehicles in 1986, at the time of 

the August 1987 proposed evaporative test procedure revisions 

no final decision had been made on the adoption of the methanol 

standards. This is why methanol-fueled vehicles were not 

specifically addressed in the August 1987 proposal. However, 

it now appears that final action may be taken on the 

methanol-fueled vehicle standards in the near future. Since 

the intent of the methanol regulations was that they be 

essentially the same 'as those for • gasoline-fueled and diesel 

vehicles, where applicable, we are proposing that the 

evaporative test procedure revisions apply to methanol-fueled, 

as well as gasoline-fueled vehicles. 

4. Concerning leadtime reauirements for implementing 

onboard controls, we have always maintained our commitment to 

provide adequate leadtime to allow safe and effective onboard 

implementation. However, we have not included a specific 

revised lead-time estimate in our SNPRM because at this time we 

feel a final decision on leadtime would best be made after all 

the safety issues and questions about potential system designs 

are clearly defined and resolved. Thus, the final decision on 

leadtime requirements will be addressed during the Final Rule 

development. 

5. There are three areas of "significantly changed 

circumstances" which affect the costs and benefits of our 

proposals. These are the implementation of Stage II in New 

York, New Jersey and St. Louis, the revised list of ozone 

non-attainment areas, and revised onboard hardware costs. All 

three of these changed circumstances are addressed in the 

SNPRM. The analysis of the first two shows their effect on 

costs and benefits to be minimal. The only significant change 

to cost-effectiveness comes from the revised onboard hardware 

costs. Onboard now has only a very small increase in hardware 

cost comoared to evaoorative controls. This increase in cost 
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is more than offset by the savings associated with the 

recovered refueling vapors over the lifetime of the vehicle, 

resulting in a net negative cost effectiveness. All three of 

these changed circumstances are discussed in detail in the 

SNPRM preamble. 

6. In response to your question concerning the emission 

benefits of onboard controls, Stage II controls, evaporative 

controls, and fuel volatility, we have not analyzed the 

benefits for each year you have reouested. However, we have 

analyzed the near-term (1995) and long term (2010) benefits of 

these programs relative to the new baseline. The results of 

this analysis are summarized in Table 6 (p. 79) of the enclosed 

SNPRM preamble. While Stage II does not appear on this table, 

the magnitude of the benefits for both onboard and Stage II 

remain unchanged from the values presented in the original 

proposal, with onboard having slightly higher benefits .than 

Stage II due to higher in-use efficiency. 

7. We fully intend to consider any comments we receive 

regarding our onboard system design. Meetings have already 

been held with Ford and General Motors to discuss their early 

testing. Full presentation of the system design will also be 

included as part of the SNPRM and we expect to receive more 

comments following its publication. 

8. In your letter you asked a number of questions 

concerning running losses. Running losses result from an 

increase in the temperature of the fuel tank while the car is 

being driven. The greater the ambient temperature, the 

temperature rise or the fuel volatility, the greater the 

running losses. The temperature rise is a function of the 

length of the drive, with longer drives causing larger 

increases in temperature (often as high as 25°F). The 

temperature rise can also be a function of vehicle 

configuration, since some designs expose the fuel tank more 

directly to heat sources than others. A major source of heat 

is hot air leaving the engine compartment, with the exhaust 

system and recirculated fuel also contributing. 

On hot summer days typical of high-ozone levels, this 

temperature rise causes current volatility fuel to literally 

boil in the tank. Depending on the vehicle design, sufficient 

vapors are generated to fulfill the engine's total fuel 

reauirements. Most manufacturers cause the pressure of the 

fuel tank to rise above atmospheric pressure at least somewhat 

by restricting the flow through the vapor vent line to the 

charcoal canister. If the pressure rise is large enough, it 

can significantly reduce the amount of vapors generated. 

However, this technique runs the risk that the pressure will 

rise above the release pressure of the filler neck cap or other 

relief valve, causing large amounts of vapors to be released 

directly to the atmosphere. Based on EPA's running loss 

testing, such venting appears to be a common occurrence. 
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It is not yet clear how the type of fuel metering system 

affects tank temperature and the resulting vapor production. 

The greatest difference in running losses appears to be due to 

the design of the canister/fuel tank purge system. Some 

vehicles are able to route essentially all their running losses 

to the engine with little or no effect on exhaust emissions, 

even with high volatility fuel. Others do not. Fuel injection 

would tend to have an advantage here over carburetion, due to 

its greater precision in fuel metering. 

EPA has tested 16 vehicles over the road to determine 

representative fuel tank temperatures over various ambient and 

driving conditions. Using this information, EPA tested 12 

current technology vehicles for running losses under a wide 

variety of ambient temperatures, trip lengths and fuel 

volatilities. Testing is nearly complete on an additional 4 

current and 6 older technology light-duty vehicles and 9 

current technology light-duty trucks. 

EPA's SNPRM includes a provision that prohibits running 

losses in-use in much the same way that we now prohibit 

crankcase emissions. No test procedure is provided, nor 

testing required. EPA did this to avoid the need to perform a 

lengthened exhaust emission test inside of a SHED at elevated 

temperatures. Also, given a detailed description of the 

operation of all vents on the fuel tank and the purge rate to 

the engine, it is a straightforward engineering test to 

determine whether running losses will occur or not. All of 

this is discussed in more detail in the enclosed SNPRM package. 

EPA's regulations have long provided for the inclusion of 

running losses along with diurnal and hot-soak emissions in 

determining compliance with the 6 and 2 gram evaporative 

standards. In fact, running losses over the FTP (9 RVP fuel, 

an 11 mile trip, relatively low temperature) are probably at or 

near zero today. The problem is that the current FTP is not 

representative of high-ozone day temperatures, in-use fuel 

volatility nor driving patterns likely to produce running 

losses. 

The fact that a number of the vehicles tested had no 

running losses over the most extreme conditions tested on 9 RVP 

with no exhaust emission effect gives us great confidence that 

the technology exists to control such emissions and need only 

be applied in the design and development process. Even on 11.7 

RVP fuel, a couple of vehicles had essentially no running 

losses and showed no increase in exhaust emissions over the 

extremes of ambient temperature and trip length. Thus, running 

losses appear controllable even with 11.7 RVP fuel using 

current technology, though the task would certainly be more 

difficult than with 9 RVP fuel. 
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9. Enclosed is a copy of the briefing you requested 

which was presented to me on August 19, 1988 by the Office of 

Air and Radiation (OAR). The three options which were 

presented to me are outlined on the final three pages of the 

briefing along with the major points of discussion. Volatility 

controls were included in all three options while excess 

evaporative test procedure revisions were included in the 

second and third options. Finally, refueling controls were 

included only in the third option. Because this briefing 

document was prepared for internal Agency deliberations, we 

request that you not release it to outside parties. 

10. As you may know, we have elected to proceed with the 

third option (volatility, excess evap. and onboard). Your 

understanding that this choice was selected over the second 

options (volatility, and excess evap. only) on the basis of 

petroleum industry opposition and test procedure costs is not 

correct. Both of these considerations are identified in the 

briefing, but were not deciding factors. Our reasoning for 

including onboard controls in our strategy is that onboard 

provides additional emissions benefits at a net negative cost 

relative to excess evaporative controls. Considering the 

magnitude and urgency of the ozone problem it is difficult to 

justify not implementing onboard controls given these 

circumstances. 

11. In your letter you raised some comments by General 

Motors (GM) on our onboard system design. GM stated that our 

system's lack of pressure controls appeared inconsistent with 

our desire to control excess evaporative emissions including 

running losses. We do not agree v/ith this position. Given 

NHTSA's experience with fuel spurting due to pressurized fuel 

tanks, we believe that pressurized systems are not necessarily 

the best way to control these emissions, but rather volatility 

controls, sufficient vapor storage capacity and improved 

purging mechanisms are appropriate. Given GM's sensitivity to 

fuel system safety issues, we are surprised to see GM 

advocating the use of pressurized fuel tanks to suppress 

running losses. It is also worth noting that the revised 

evaporative test procedure does not preclude the use of 

pressurized fuel tanks, but requires that such systems be 

designee to prevent the venting of gasoline vapors while the 

vehicle is running or when the fuel cap is removed for 

refueling. 

12. The question of the leadtime required in order to 

implement volatility controls for the summer of 1989 is 

something we have been looking at closely. Based upon comments 

from petroleum refiners, we believe that publication of the 

final rule by early 1989 will provide sufficient leadtime. We 

understand that it is critical that volatility controls are in 

place for the next ozone season and you can be assured that we 

are committed to making that happen. 
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13. As you know, we are currently working hard to 

finalize the volatility and onboard rules as soon as possible. 

We feel that this is the appropriate course of action given the 

urgency of the ozone non-attainment problem. However, we do 

not intend to compromise our analyses in any way. The SNPRM 

package was initially sent to OMB for review after completion 

of Red Border review. Also, we intend to have a public hearing 

and thirty-day comment period following the publication of the 

SNPRM and will address all comments received as we consider a 

Final Rule. We do not believe that this schedule in any way 

compromises our ability to do a thorough analysis of all 

relevant issues nor do we feel that volatility controls can be 

finalized any sooner than this as a separate rule. However, if 

unexpected delays develop at a later time, we are prepared to 

separate out an interim volatility package to assure that the 

first phase of volatility control will be in place for next 

summer. 

In response to your October 14 letter, I will clarify 

again our intentions related to the onboard reproposal. As we 

stated to the public in the August 1987 proposal and as we have 

since explained to you, OMB and others, we committed to reopen 

the record of this rulemaking when the Agency receives the 

safety comments from NHTSA and to repropose the rule for 

comment to assess changed circumstances. 

As mentioned previously in this response, there are 

important issues other than safety that will be addressed in 

the reproposal. It was our intention to have OMB begin to 

review the non-safety issues as soon as possible. Those issues 

are separate from onboard safety and, therefore, will not be 

affected by the NHTSA review. In fact, we had informed OMB 

staff on several occasions, most recently in a meeting with 

them on September 14, that we planned for them to first review 

the parts of the reproposal that were unrelated to onboard 

safety. Then, after receiving NHTSA's comments, we would send 

them to OMB and the package would be complete. We never 

expected OMB to concur on the package before NHTSA's comments 

were available. As you can see, our actions were thoughtfully 

planned to move the rulemaking forward in a sensible manner 

fully consistent with our previous commitments. 

Subsequent to the preparation of the previous portions of 

this response, we received NHTSA's safety comments on October 

24. On October 25 we delivered to your office a copy of our 

August 1988 safety report as you requested. We understand 

NHTSA has given you a copy of their comments. Note that we are 

placing both of these documents in the public docket for this 

rulemaking and making copies available to interested parties. 

Further, we are now sending the entire SNPRM back to OMB for 

their review. 
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In closing, I would like to thank you for your concern in 

these matters. We at EPA have always prided ourselves on 

performing thorough and objective analyses and on our 

willingness to persevere when working through tough issues. I 

firmly believe that we are continuing in that tradition as we 

work toward the implementation of fuel volatility and refueling 

controls. 

Lee M. Thomas 

Enclosures 

cc: Docket A-87-11 

Docket A-85-21 

The Honorable Joseph R. Wright Jr. 

Acting Director, OMB 

The Honorable Charles A. Bowsher 

Comptroller General, GAO 

The Honorable Diane K. Steed 

Administrator, NHTSA