Self paced silent presentation of some safety tips to avoid dangerous inhalation of benzene as we drive, fill-up and park in your garage. Benzene is a potent carcinogen that causes cancer, especially leukemia. We are exposed to much greater concentrations of benzene than OSHA and NIOSH say is safe. But there are some very simple precautions that you can take to significantly lower the dosage you are getting now. You just have to be made aware of the difficult medical situation that driving on gasoline has put us into.

1. Defend Yourself From
Benzene Emissions
When Using Gasoline
Bob Falco, PhD
Professor of Mechanical Engineering
Director, Institute for Energy Resourcefulness

2. Cancer rates in the US
Newsweek Oct 2012

4. 1/3 of the cancer risk
in the US is due to vehicles
―The average cancer risk in 1999
for Americans was forty-eight in a
million, and 29% of this risk was
attributable to mobile sources—
which works out to a mobile-source
cancer risk for the average
American of about fourteen in a
million.‖ in an ADDITIONAL 4340 deaths every year!
This results
EPA Technology Transfer Network National Air Toxics Assessment, 1996

5. Gasoline contains Benzene, and Vehicles
create additional Benzene from burning
exhaust in their catalytic converters
Created in the catalytic
Added at the refinery
converter

6. Benzene is the major
Carcinogen
Benzene produces leukemia

7. No agreed upon
minimum
exposure that is
safe!
Health numbers differ by
100 million times
Regulatory advisory numbers
differ by 1000 times
We don‘t know
how dangerous
benzene is!!! EPA Jan 2012

9. The EPA Cancer Odds
Increased cancer deaths
 13-45 micro grams per cubic meter  1 in 10,000
increase in cancer deaths (30,000/year)
 1.3-4.5 micro grams per cubic meter  1 in 100,000
increase in cancer deaths (3,000/year)
 .13 to .45 micro grams per cubic meter  1 in
1,000,000 increase in cancer deaths (300/year)

10. Ways You Are Exposed
to Benzene from
Gasoline
and the
Amounts Inhaled

12. Vapor release during
gasoline refueling
We can‘t see the benzene that this special camera shows as black smoke,
but we can smell it.

13. Do you smell the sweet odor of
benzene when you fill-up?
BENZENE HAS AN ODOR THRESHOLD OF 5
MILLEGRAMS PER CUBIC METER
Thus, if you are smelling the sweet odor of benzene as
you fill-up you are being exposed to 1000 times that
determined the 1 in 100,000 number, so that
a 1 in 100 chance of getting cancer.
Of getting leukemia!

14. EPA benzene vapor protection
Phase II installed in 1993 -60% effective
ORVR in all vehicles newer than 2006 – 98% effective

15. Benzene emissions during fill-
up if ORVR is 98% effective
When filling your gas tank the EPA expects emission of 12 ppm over the5 minute fill-up.
The industrial standard set by OSHA for the Short Term Exposure Limit is 5 ppm over 15min.
The industrial standard set by NIOSH for the Short Term Exposure Limit is 1 ppm over 15
min.
Thus,
The amount coming out of your tank is 2.5 times the OSHA STEL
and,
12 times the NIOSH STEL

16. Recommendations
To avoid evaporative emission exposure:
1. Do not stand over the gas tank while filling it.
2. Lock the nozzle ‗open‘, and walk away.
3. Close the windows and doors of your car when filling –
especially if you have children in it.
Note: the benzene level in the convenience store are likely
much higher than outdoors.

17. Exhaust Emissions
 Three-way catalytic converter does reduce benzene
emissions in the normal range of driving.
 However, when accelerating from rest or driving at
high speeds the catalytic converter produces more
benzene.
 Furthermore, as shown a few slides ahead, when the
catalytic converter is cold, as it is for a few minutes
after starting your car, it the
benzene emissions.

18. The Exhaust Plume
1 in 10,000
Car following
in lane
Where should you
position your car?

19. The Exhaust Plume
1 in
700,000
1 in 10,000
At 2 ½ car lengths you are exposed to 1/36 the amount
of benzene as at the tail pipe.
If you stay right behind the vehicle in front of you,
your car is in taking a good portion of the plume, which has benzene
concentrations that result in an additional 1-in-10,000 chance
of cancer if inhaled regularly.

20. Catalytic Converter
Benzene Generation
Benzene (pre-catalyst) or,
Benzene (post-catalyst)
during cold start
75 mph
At high speed, greater than 75 mph, you should drive even further back .

21. Cold Starting
 When your car is cold started, or you are driving
behind one that has just been started, the catalytic
converter is not removing the benzene (left plot on
previous slide).
 In this condition the curve on the left (previous slide)
shows that the amount of benzene is very, very high at
all speeds.
 Often, when in city driving, you are on the road along
with your neighbors going through lots of lights on the
way to work while your car is warming up. Conditions
are very bad.

22. Recommendations
The spreading of the exhaust plume is asymmetric and you
get its full effect as you follow behind in-lane.
1. When in moving traffic, try to stay at least 2 ½ car
lengths behind the car in front of you.
Your dose will be 1/36 of the emission level at the
exhaust pipe.
2. When stopping for a light, stop at least 1 car length
behind the vehicle in front of you. Although the ―acceleration
blast‖ (see last slide) is up to 20-30x steady state, it will
diffuse to ½ - ¼ that which exists at the exhaust pipe at 1 car
length distance. This is still a high dose. And is especially
high if you‘re in traffic full of newly started cars.

23. Gas Tank Cap Leaks
 It is estimated that 200 lbs of gasoline leaks from the
average cars tank through the gas cap per year. This
is 25 gallons.
 The biggest problem is that this gas will collect in your
garage.
 So you get a good dose as you enter your garage.
 But, perhaps worse, if you have an attached garage, it
will get into your house.

24. Recommendations
 Check the tightness of the gas cap. Replace it if leaks
are found. Benzene is very volatile and leaks easily.
 Let your garage ‗air out‘ before entering it.
 Make sure the garage door leading into your house is
well sealed.
 Vent your garage.

25. Benzene effects are
cumulative

26. EPA has just enforced
the 0.62% benzene limit.
 Reduction from 1.05%
 Vapor emission during filling will be halved, but still over the OSHA
and NIOSH STEL limits by 125% and 600%
 This does little to change the exhaust emission picture, for as the
Swiss studies show:
 when cold starting,
 when accelerating,
 and when driving at high speed,
the benzene emissions can be up to 100x the steady state rates.
 And, the EPA allows refineries to trade benzene credits. A result is
that some regions are suffering – see next slide.

27. Oregon example

28. Conclusions
 The effects of the exposure to benzene are long term.
Think of them as you do the effects of smoking.
 The western world, and particularly the US has very high
rates of leukemia compared to the rest of the world.
I leave it to you to decide whether to ignore the precautions.
I also want to make you aware that your car does not need
to run on gasoline, and can actually run better on alcohols
like ethanol and methanol (see presentations in references
on the following slide).

29. References
 Falco -- YouTube Channel on Alternative Fuels
 http://www.youtube.com/user/bobfalco12345/videos?flo
w=grid&view=1
 Falco SlideShare Site
 http://www.slideshare.net/BobFalco