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OAR Box 1818 

Prepped by Ollie Stewart 

Document Number: 

13) ll-C-9 

Docket Number: 

A-87-11 

Printed 11/6/2008 3:12:42 PM Sheet 13 of 79 
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A-wi /- c -c\ 

6 . ^ \ UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

JUL I 3 1987 

ANN ARBOR. MICHIGAN 48105 

OFFICE OF 

AIR AND RADIATION 

Mr. Ralph Hitchcock, Director 

Office of Vehicle Safety Standards 

National Highway Traffic Safety 

Administration (NRM-10) 

400 7th Street, SW 

Washington, DC 20590 

Dear Mr. Hitchcock: 

As part of our study of refueling controls we have been 

investigating the costs and benefits of bladder tank 

technology. This technology offers the potential to both 

control refueling emissions and enhance the safety of 

vehicles. As part of this investigation, my staff has recently 

completed a preliminary analysis of fuel tank-related fires. 

The results of this analysis will be used in the future to aid 

in estimating the overall societal benefits 

A copy of this analysis is enclosed for your 

appreciate any comments, ideas, or new data 

staff may have regarding this analysis, 

questions, feel free to contact Kathleen Steilen of my staff at 

FTS 374-8274. Thank you for your assistance in reviewing and 

commenting on this analysis. 

of bladder tanks, 

review. We would 

that you or your 

If you have any 

Chester J./France, Chief 

Standards Dev/elopment and Support Branch 

Enclosure 
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../ t0Sr^ 

J (T>. \ UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

3

- X^Lr-1 AN N AR30R. MICHIGAN 48105 

\ <' 

JUN I 0 1537 OFFICE OF 

AIR AND RADIATION 

MEMORANDUM 

SUBJECT: Analysis of Fuel Tank-Related Fires 

FROM: Kathleen A. Steilen, Chemical Engineer "iCc3CrJbuv\ 0. 

Standards Development and Support Branch 

-•<-•*- \-^ 'Np. 

TO: 

THRU: 

Charles L. Gray, jr., Director 

Emission Control Technology Division 

Glenn W. p 

Standards 

assavant, Project Manager ^(JL &T** J<n ilU, lLu^t^J:y 

Development and Support Branch o 

Chester J. Fra nee, Chief J/yf 

Standards Development a 

Introduction 

Recently several parties have expressed concern regarding 

the safety of onboard refueling emission controls. Both the 

Insurance Institute for Highway Safety (IIHS) and National 

Highway Traffic Safety Administration (NHTSA) have commented to 

EPA that adding canister-based onboard controls to current 

motor vehicles v/ould add some complexity to the fuel system 

which could increase the risk of post-collision fires in motor 

vehicle accidents. in a separate action, we have conducted a 

further evaluation of the safety implications of canister-based 

onboard systems to address the concerns raised by IIHS, NHTSA 

and others. 

As a further response to concerns regarding the safety of 

onboard systems, we are investigating the possibility of the 

use of collapsible fuel bladders as an alternative refueling 

control approach. Since no vapor space exists in a collapsible 

bladder, refueling emissions can be reduced substantially or 

virtually eliminated; in addition they have the potential to 

control, diurnal evaporative emissions. Also, collapsible 

bladders may have some safety advantages over canister-based 

systems, since the external plumbing and a larger canister are 

not needed. Perhaps even more importantly, collapsible 
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bladders have the potential to reduce the fire risk now found 

in current -motor vehicles since they would provide an 

additional shell of protection in the event of a fuel tank 

rupture. 

The purpose of this memorandum is to provide an estimate 

of the potential in-use safety benefits of collapsible fuel 

bladders. It begins with a summary of the currently available 

data on the annual number of post collision and fuel tank 

related fires and the subsequent fatalities, injuries, and 

property damage. This is followed by a discussion of how this 

data was analyzed and adjusted to project the number of fuel 

tank fires, fatalities, injuries, and property damage in 1990 

and beyond when refueling controls would be required in the 

present draft NPRM. The memo closes with a brief outline of 

EPA's future steps in this study of using collapsible fuel 

bladders as an alternative refueling control approach. 

Summary of Available Data 

The available data on fuel tank related fires and 

subsequent effects are limited, and no single body of data 

exists which accurately assesses the overall hazards. 

Virtually all of the available data arises initially from 

police and fire marshal1 reports from different states and 

while police reports from Michigan, Illinois, North Carolina, 

Maryland, and Pennsylvania are quite useful, these records 

alone are not adequate to characterize the problem. Data from 

these records must be extrapolated to get an estimate of 

national values. 

Further, the nature and extent of the fire crash data 

varies in the different state reports. For example, some state 

accident reports are very explicit in evaluating fires from 

fuel leakage, the type of accident (front end, rear end, 

rollover) and the accident severity. Others are less complete 

perhaps only reporting information on fires, and fatalities 

without much supporting detail. 

Two Federal agencies and several different motor vehicle 

safety experts have used the available information to develop 

data bases or other analyses which can be used to assess the 

number of fuel tank related fires and subsequent effects. Each 

of these is described briefly below, together with the 

important information drawn from the source. 

1. Fatal Accident Reporting System (FARS) (1980-1984) 

This data base, maintained by NHTSA, lists all 

police-reported accidents in which a fatality occurs. The 

source specifies whether a fire occurred but does not indicate 

the source of the fire or whether or not the fire was the 

direct cause of the fatality. By using data from accidents 
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with fatalities only, the reported motor vehicle accidents are 

generally more severe. Use of this data alone could 

misrepresent or overestimate the overall fire hazards of 

current vehicles. 

The most useful information from FARS is the number of 

fatalities from all motor vehicle accidents and those, with post 

collision fires. The data covers all model year vehicles, both 

pre- and post-FMVSS 301 (1976) averaged for the period 

1980-1984. The key data from this source are summarized below: 

1605 annual post-collision motor vehicle fires in 

which a fatality was reported. 

49,037 annual fatalities resulted from all motor 

vehicle accidents. 

Of these total fatalities, 1655 fatalities (3.3%) 

included a post-collision fire. (There were about 

50 fires in which more than one person died.) 

2. National Fire Incident Reporting System (NFIRS) 

This data base, maintained by the Federal Emergency 

Management Agency (FEMA), includes all types of fires, 

including motor vehicle fires. It receives a sampling of the 

total fires (about 40 percent in 1985) and extrapolates 

national statistics from these. This system particularly 

specifies the number of fires which begin in the fuel tank area 

and the deaths, injuries and property damage resulting from 

these fires, but the system does not specify these exclusively 

for post collision fires. Since the statistics are compiled on 

an annual basis, the data covers all model year vehicles both 

pre- and post-FMVSS 301. 

The important data in NFIRS for 1985 includes: 

552,000 total annual motor vehicle fires (of all 

types). 

11,000 motor vehicle fires (2.0%) which began in the 

fuel tank area. 

220 fatalities in motor vehicle fires which began in 

the fuel tank area. 

640 injuries in motor vehicle fires which began in 

the fuel tank area. 

$46 million of property damage from motor vehicle 

fires which began in the fuel tank area. 

3. "Evaluation of Federal Motor Vehicle Safety Standard. 

301-75, Fuel System Integrity: Passenger Cars", NHTSA 

Report, Glenn Parsons (1983): 

This NHTSA report evaluated the effectiveness of FMVSS 

301, and thus contains data on the in-use accident and fire 

experience of pre- and post standard vehicles. Tables 1 and 2 
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show the distribution of impact type and vehicle damage 

severity in . accidents involving both pre- and post-standard 

vehicles. Table 1 which presents the frequency of accidents 

from the various impact types shows that rollover accidents are 

rare occurrences and most accidents are frontal impacts. Table 

2 presents the damage severity sustained by each vehicle 

involved in an accident based on a Vehicle Damage Severity 

(VDS) scale. A VDS of l represents very minor vehicle damage, 

where as a VDS of 8 represents very extreme damage. As 

expected, this table shows that accidents with Lo-Moderate 

severity damage (VDS=2,3,4,5) are more frequent in comparison 

to major severity accidents (VDS=6,7,8). 

Table 3 presents the fire rates for pre- and post-standard 

vehicles by impact type and damage severity. The data shows 

that rollover and rear end collisions, especially those with 

major damage severity, have the highest fire rates. 

Furthermore, this table shows that FMVSS 301-75 gave a greater 

reduction in the fire rates for major severity accidents (50.6 

percent) than for Lo-Moderate severity accidents (22.4 percent). 

This NHTSA report also provides good data on the number 

and degree of injuries which result from vehicle accidents and 

post-collision fires. It divides the injuries into four 

types: fatal injuries, incapacitating injuries, 

non-incapacitating injuries, and possible injuries. Some 

additional information generated in this report is presented 

below, but the key data with regard to fire rates are shown in 

Table 3: 

20,600 annual motor vehicle fires resulting from 

passenger car accidents. 

1,099 annual fatalities in passenger car accidents 

with fire (average from FARS for 1978-1981). 

Total injuries in all passenger car accidents: 

385,892 incapacitating injuries 

865,642 non-incapacitating injuries 

1,095,180 possible injuries 

Injuries in passenger car accidents with 

post-collision fire: 

3867 incapacitating injuries 

3836 non-incapacitating injuries 

2486 possible injuries 

4. "Fire in Motor Vehicle Accidents", Peter Cooley (1974): 

This Highway Safety Research Institute (HSRI, now UMTRI) 

report by Peter Cooley provides data on the total number of 

vehicle fires and the resulting fatalities. He further 

analyzes the fatalities involved in post-collision fires and 

determines whether the fatality was "accompanied by" or 

"directly caused by" the post-collision fire. Unfortunately, 
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Table 1 

Distribution of Accidents by Impact Type 

Impact 

Type 

Frontal 

Rollover 

Rear end 

Pre-Standard 

Frequency (%) 

72.1 

1. 7 

26.2 

Post-Standard 

Frequency (%) 

69.8 

1.6 

28.6 

Overall 

Frequency (%) 

70.7 

1 .7 

27.7 

Based on Michigan data for calendar year 1980 
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Table 2 

Distribution of Accidents by Vehicle Damage Severity 

Vehicle 

Damage 

Severity r-l 2 

3 

4 

5 

6 

7 

8 

Pre-Standa 

Frequency 

3.858 

25.595 

26.134 

20.220 

12.447 

6.552 

3. 112 

2.076 

rd 

(%) 

Post-Stand 

Frequency 

2.892 

26.108 

27.162 

20.532 

12.398 

6.350 

2.821 

1.707 

ard 

(%) 

Over All 

Frequency (% 

3.26 

25.92 

26.78 

20.42 

12.42 

6.43 

2.93 

1.85 

Based on Michigan data for calendar year 1980. 
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Table 3 

Fire Rates for Pre- and Post-Standard 

Vehicles by Impact Type and Damage Severity 

tt of fires/# of vehicle crashes = fire rate(xl0-3) 

Lo-Moderate Severity Majority Severity 

(VDS = 2,3,4,5) (VDS = 6,7,8) 

Pre-Standard 

Front end 360/229,433 = 1.569 91/9465 = 9.614 

Rear end 139/99,663 = 1.395 90/6304 =14.28 

Rollover 14/2946 = 4.752 49/3389 = 14.46 

TOTAL 513/332,042 = 1.545 230/19,158 = 12.01 

Post-standard 

Front end 311/261,002 = 1.192 79/14,425 = 5.477 

Rear end 139/119,141 = 1.167 40/6944 = 5.76 

Rollover 10/3541 = 2.824 29/3599 = 8.05 

TOTAL 460/383,684 = 1.199 148/24,968 = 5.93 

Reduction from Standard 22.4% 50.6% 

Based on Michigan data for calendar years 1978, 1979, and 

1980. 
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his data does not determine the source of the fire (i.e., fuel 

tank). This.data is based solely on pre-standard vehicles. 

17,000 annual fires result from motor vehicle 

accidents. 

720-1250 fatalities are accompanied by these fires. 

450-650 fatalities are directly- caused, by the 

vehicle fires. 

5. "General Motors and Fuel System Collision Fires" (1974): 

This study provides GM's point of view on the fire hazards 

of motor vehicles. It offers good statistics on the number of 

fatalities caused by post-collision fires and more 

specifically, fuel system collision fires. It relates only to 

pre-standard vehicles. Key data includes: 

560-1870 annual fatalities due to collision fires. 

250 annual fatalities due to a vehicle- fuel system 

collision fire. 

6. "A Perspective on Automobile Crash Fires", SAE 850092, 

Warner, James and Woolley, (1985): 

This SAE paper analyzes previous studies on automobile 

crash fires. It provides a range of fatalities caused by 

post-collision fuel-fed fires, and concludes that 1-1.5 percent 

of all occupant fatalities are caused by post-collision 

fuel-fed fires independent of FMVSS 301 improvements. 

Analysis of Data 

As can be seen from the descriptions above, the six 

available data sources and published reports provide different 

types of information covering different time periods. However, 

with careful analysis, this information can be used to generate 

estimates of fuel tank related fires, fatalities, injuries, and 

property damage for vehicles operating in the post-1990 time 

frame. The year 1990 is intended to reflect when essentially 

all light-duty vehicles and light-duty trucks in-use would be 

in compliance with FMVSS 301. Additionally, a year had to be 

chosen to adjust data by VMT for such a time frame. 

Before this data can be used to generate the desired 

estimates two adjustments are necessary to get all the data on 

a common basis. First, it is necessary to get all data in 

terms of post-standard fire rates, since by the time bladders, 

could be available most vehicles in-use would be 1976 or later 

model year. The fraction of the fire data contributed by 

pre-standard vehicles was determined using the estimated 

percentage of VMT by these vehicles when the data was taken and 

adjusting it based on the effectiveness of FMVSS 301 given in 

the aforementioned NHTSA report. Since it is reasonable to 
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assume that most rear end and rollover accident fires occur in 

the fuel tank, area, a fuel tank related fire reduction factor 

for FMVSS 301 was calculated using the pre- and post-standard 

rates for rear end and rollover collisions shown in Table 1. 

These overall post-collision and fuel tank-related fire 

reduction factors were estimated to be 32.7 and 36.9 percent, 

respectively. 

Second, after the data is adjusted to post-standard fire 

rates it is also necessary to consider that increasing VMT 

between when the data was generated and 1990 would increase the 

absolute number of fuel tank fires and related aftereffects. 

It is reasonable to project that absent other measures, fires 

and subsequent fatalities, etc., would increase as VMT 

increases. Thus as a simple adjustment, all data was adjusted 

to 1990 using the ratio of the 1990 total VMT to the total VMT 

of the year(s) in which the data was generated. 

One other adjustment which was considered but not 

incorporated is the effect of vehicle aging on fire rates. If 

vehicle aging does affect fire rates, the data adjustments for 

pre- to post-standard vehicles would have to be adjuste'd 

further. This concern arises because the pre- and 

post-standard fire rate data used to develop the adjustment 

factor did not use all vehicles of the same age. The 

post-standard fire rate was based on vehicles 0-4 years old, 

the pre-standard rate was based on vehicles 3-8 years old. 

Thus there is the possibility that the adjustment factor could 

be too large because it incorporates the effect of different 

fire rates on different age vehicles, in addition to the 

improvements brought by the safety standard. 

Fire rates (fires per crash) may vary by vehicle age 

because changes in driving patterns (less high speed freeway, 

more lower speed urban area), ownership, fuel system component 

deterioration, and lack of maintenance with vehicle age may 

have an overall effect on the possibility of a fire in the 

event of an accident. The net effect of these factors was 

evaluated using data from the NHTSA technical report with a 

preliminary conclusion that the effect of aging is probably 

small. However, an accurate determination (either 

quantitatively or directionally) cannot be made until more 

information becomes available later this year when Glenn 

Parsons of NHTSA updates his evaluation of FMVSS 301-75 based 

on more recent data. It is interesting to note that the 1985 

FARS data suggest that the percent of vehicle accidents (not 

fires) by model year is directly proportional to registrations 

of that model year, not VMT. 

Development of 1990 Vehicle Fire Data 

The data on motor vehicle fires extracted from the six 

sources were collectively analyzed to estimate the annual 
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number of post-collision and fuel tank related fires and the 

resulting fatalities, injuries and property damage. As 

previously mentioned, to be useful the characteristics of all 

available data must be put in terms of a common basis. 

Therefore, the fire data was scaled as discussed above to 

represent post standard vehicles in the year 1990 when 

essentially all vehicles will meet FMVSS 301. 

Very few sources directly provide statistics especially 

for fuel tank related fires. In fact, only three of the 

studied sources provide such statistics: NFIRS, the General 

Motors study, and SAE paper 850092. Another method to estimate 

the statistics for fuel tank fires in particular is to 

approximate the percentage of total post-collision fires which 

are fuel tank related. Since it is logical to assume that most 

of the fuel tank related fires result from rollover and rear 

end collisions, this percentage can be estimated from the total 

fraction of these collision types. Using this assumption and 

the NHTSA report by Glenn Parsons, it can be calculated that 

fuel tank fires account for approximately 36 percent of the 

total collision fires. Post-collision fire data from the 

remaining sources can be used with this percentage factor to 

estimate the number of fuel tank related fires and their 

subsequent effects. 

Table 4 presents the 1990 post standard motor vehicle fire 

data generated from the six sources used in this analysis. The 

data presented includes the number of vehicle fires and/or 

their aftereffects for post collision fires and particularly 

for fuel tank fires. As previously mentioned, only the NFIRS, 

GM Study, and SAE 850092 directly report data for fuel tank 

fires. Fuel tank fire statistics for the remaining sources 

(FARS, Parsons' report, Cooley"s report) were estimated by 

scaling the post-collision data with the percentage of fuel 

tank fires approximated from Parsons' report (36 percent). 

Therefore, the data in Table 4 encompasses all of the available 

data and presents a reasonable range of the fire hazards for 

motor vehicles in the year 1990. 

The data from the six sources presented in Table 4 can be 

summarized for both the post-collision and fuel tank related 

fires as presented below: 

• Post-Collision Motor Vehicle Fires 

15,300-19,600 annual fires 

400-1700 fatalities 

3700 serious injuries 

3600 moderate injuries 

• Fuel Tank-related Fires 

5500-11,200 annual fuel tank-related fires 

150-840 fatalities 

650-1320 serious injuries 
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• • • • 

1990 PostSource/Statistic 

FARS 

Fires with Fatalities 

Fatalities 

NFIRS 

Vehicle Fires 

Fatalities 

Injuries 

Property Damage 

Parsons' Report 

Vehicle Fires 

Fatalities 

Injuries: 

Incapacitating 

Non-Incapacitating 

Possible 

Cooley's Report 

Vehicle Fires 

Fatalities 

GM Study 

Fatalities 

SAE 850092 

Fatalities 

Table 4 

-Standard Vehicle Fire 

Post Collision 

Fires 

1629 

1679 

19,550 

1043 

3669 

3640 

2359 

15,313 

405-1126 

505-1685 

1 

Data 

Fuel Tank 

Related Fires 

586 

604 

11,150 

223 

649 

47M 

7038 

375 

-

1321 

1310 

849 

5513 

146-405 

211 

560-839 
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1310 moderate injuries 

-.. $47 million property damage 

These statistics represent a reasonable range for the fire 

hazards of motor vehicles for the year 1990, when refueling 

controls are required in the current draft NPRM. The fuel tank 

related fire data, in particular, show the potential in-use 

benefits of fuel bladder systems if implemented as alternative 

refueling controls. 

Future Steps 

To complete this fuel tank-related fire analysis EPA plans 

to fully coordinate our motor vehicle fire conclusions with 

NHTSA. As part of this coordination, we have already met with 

them to present an outline of our data and analysis and to seek 

any comments or suggestions. We have also met with FEMA to 

discuss our study, and they are providing us with further 

information from their NFIRS database. Additionally, we are 

investigating in greater detail the current fire hazards of 

heavy-duty trucks. Once we incorporate all of this subsequent 

fuel tank fire data into our analysis, we can complete our 

investigation, with NHTSA's coordination. 

We are also in the process of analyzing the potential 

cost/benefit of fuel bladder systems. This analysis will 

consider all environmental and safety benefits associated with 

fuel bladders and determine the possible cost range of such 

bladders so that the costs are equivalent to the benefits 

obtained. Other future actions by EPA include a detailed study 

of the costs of fuel bladder systems as refueling controls and 

a test plan to determine the effectiveness of collapsible 

bladders in controlling both refueling and evaporative 

emissions.