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#439 - Tire Dust, 26-Apr-1995

The automobile did not come to dominate American transportation by
chance or by public choice. It happened as part of a plan by auto
makers to buy up and destroy mass transit companies. General Motors led
the way. As recently as the 1920s, many American cities and towns were
connected by a network of electric railroads and interurban trolleys.
Within cities, electric street railways, trolleys, and elevated trains,
moved large numbers of people easily and cheaply, with minimal
congestion and pollution. But steel-wheeled electric/rail mass transit
systems did not serve the needs of the automobile manufacturers and
their allies in the steel, rubber, glass, concrete, and oil industries.

Beginning in the 1920s, General Motors began investing in mass transit
systems. According to historian Marty Jezer (and Congressional hearings
held in 1974), between 1920 and 1955, General Motors bought up more
than 100 electric mass transit systems in 45 cities, allowed them to
deteriorate, and then replaced them with rubber-tired, diesel-powered
buses.[1] Buses are more expensive, less efficient, and much dirtier
than electric/rail systems. (And of course automobiles are even less
efficient than buses, by far.) In 1949, General Motors, Firestone
Rubber, and Standard Oil of California were convicted by a federal jury
of criminally conspiring to replace electric mass transit with GM-
manufactured diesel buses; in a noteworthy illustration of justice for
corporations, the court fined GM $5000 and forced H.C. Crossman, the GM
executive responsible for carrying out GM's policy, to pay $1.00.

Cities where GM managed to eliminate electric/rail systems, and replace
them with buses and private cars, included New York, Philadelphia,
Baltimore, St. Louis, Oakland, Salt Lake City, and Los Angeles.

Many people think of Los Angeles as the original automobile city.
However, before GM converted the city to buses and private automobiles,
Los Angeles was served by the largest electric/rail mass transit system
in the nation. The Pacific Electric Railway ran more than 1000 trains
per day over 760 miles of rail lines to such outlying stations as
Redlands, Corona, Santa Monica, Redondo Beach and Balboa, carrying
light freight as well as passengers. Its last line, to Long Beach, was
abandoned in 1961 --the same year the ingredients of smog were first
identified in L.A.'s toxic air.

During this same period, GM worked to convert electric-powered commuter
railroads to diesel-powered locomotives, which were far more expensive,
more complex, and less reliable than electric locomotives, thus
requiring more maintenance, and contributing significantly to the
demise of the nation's railroad system. For example, the New York, New
Haven, and Hartford line showed a profit during 50 years of operation
until 1956, the year it began converting to diesel locomotives; by 1961
it was declared bankrupt and a report by the Interstate Commerce
Commission censured GM for contributing to its demise.

We all know some of the consequences of converting the American
transportation system from electric/rail to rubber-tired vehicles. The
threat of global warming from combustion of fossil-fuels (oil and
gasoline) is one part of the problem. Lung cancer from diesel exhaust
is another.[2] But recently, another aspect of our transportation
system has appeared in scientific and medical literature: serious
pollution from rubber tire fragments (tire dust) released by tire wear.

When a rubber tire, bearing the weight of a vehicle, rolls across an
asphalt or cement surface, tiny fragments of rubber break off from the
tire and become airborne. In the 1970s and early 1980s, scientists
working for the rubber tire industry and for the U.S. Environmental
Protection Agency concluded that these tire fragments were too large to
enter the human lung and so presented no threat to human health.

However, new research published this year by allergy specialists has
reached a different conclusion: these new studies show that about 60%
of tire fragments (tire dust) are so small that they can enter the deep
portions of the human lung where the latex rubber in the tire dust may
cause allergic reactions ranging in severity from rhinitis (runny
nose), conjunctivitis (tearful eyes), to hives (urticaria), bronchial
asthma, and occasionally even a life-threatening condition called
anaphylactic shock.[3] Asthma, and asthma deaths, have increased
dramatically during the past 20 years, especially among children, and
specialists have been searching in vain for causes. (See REHW #374.)

Allergy to latex rubber has become more common in recent years,
especially among health-care workers who are exposed more or less
continuously to latex gloves, tubes, sheets, and other latex-containing
products.[4] An estimated 17 million Americans have an allergic
reaction to latex. Examination of latex allergy has shown it to be a
true allergy; in technical jargon, it is mediated by IgE antibody to
proteins that are present in the natural rubber produced from the
tropical rubber tree (Hevea brasiliensis).

Allergic reactions to tire dust may be increasing for several reasons.
The number of tires has increased steadily during the last 20 years;
the proportion of latex in tires has been increasing; and tire
construction has changed from bias ply to radial. Tire dust from
radials is finer and thus more respirable, meaning it enters the
deepest part of the human lung more easily.

The human nose and throat filter out airborne particles larger than 10
micrometers in diameter, but about 60% of tire dust is smaller than 10
micrometers in diameter and can thus enter the lungs where it can cause
allergic reactions in some people.

In 1974, when there were 524.3 million tires in use in the U.S. (on
cars, motorcycles, trucks, and buses), tire industry scientists
estimated that 600,000 metric tonnes (1.3 billion pounds) of tire dust
were released by tire wear in the U.S., or about 2.5 pounds (a little
over one kilogram) of dust released from each tire each year. In 1991,
there were 782 million tires in use in the U.S.; if each tire releases
2.5 pounds of dust per year, tire dust released in 1991 would total 1.9
billion pounds. A billion is a thousand million. In Los Angeles alone,
at least 5 tons (10,000 pounds) of tire dust are released into the air
each day.

Radial tires create a finer, more respirable dust than do bias ply-
constructed tires, and the percentage of tires that are radial grew
from 2% in 1970 to 95% in 1990, so tire dust released in the 1990s
probably enters the lungs more readily than tire dust did in previous
decades. Conceivably, this might explain part of the recent increases
in asthma in the U.S.

In 1994, careful measurement of air near roadways with moderate traffic
revealed the presence of 3800 to 6900 individual tire fragments in each
cubic meter of air, more than 58.5% of them in the fully-respirable
size range. When these fragments were examined chemically, and by mass
spectroscopy, they were shown to contain latex. Furthermore, they were
shown to produce allergic reactions, comparable in every way to the
allergic reactions caused by dust from a pulverized latex glove.[3]

How might these problems be resolved? Allergic reaction to latex was
first described in 1979; after AIDS became a major medical problem,
more and more medical workers started wearing latex gloves and latex
allergies came to light. Some 7% to 10% of all health care workers now
exhibit an allergic reaction to latex.

Recently, latex from a new source, the guayule plant (Parthenium
argentatum), which grows well in the southwestern U.S., has been shown
to not cause latex allergy in exposed people.[6] Latex from the guayule
plant could become a growth industry for American farmers; presently,
about seven million tons of latex are produced each year from the
tropical rubber tree, Hevea, worldwide.

In the case of rubber tires, the problem is more complex than mere
latex allergy, although this may well turn out to be a serious public
health problem by itself. The high dollar cost of truck freight,
private automobile commuting, and maintenance of our highway
infrastructure must be counted as major sacrifices to our rubber-tired
transportation system. Furthermore, fine particle air pollution now
kills an estimated 60,000 Americans in cities each year.[7] And global
warming is a serious threat to many nations from many viewpoints. (See
REHW #429, #430.)

However, from the viewpoint of our most important national treasure --
our self-governing democracy --the systematic sabotage of the nation's
electric/rail mass transit systems by automobile corporations points up
a most serious problem: the ability of "private" corporations to effect
sweeping changes in our public life and culture, without public
accountability or even debate. If we ever hope to achieve a sustainable
environment, and re-establish a fair economy and a working democracy,
this is a key problem we will have to acknowledge and address.

--Peter Montague


[1] Marty Jezer, THE DARK AGES; LIFE IN THE UNITED STATES, 1945-1960
(Boston: South End Press, 1982), pgs. 138-146.

[2] See U.S. Environmental Protection Agency, HEALTH ASSESSMENT
DOCUMENT FOR DIESEL EMISSIONS [External Review Draft; 2 volumes:
EPA/600/8-90/057Ba and EPA/600/8-90/057Bb] (Research Triangle, N.C.:
U.S. Environmental Protection Agency, December, 1994). And see REHW

[3] P. Brock Williams and others, "Latex allergen in respirable
Vol. 95, No. 1, Part 1 (January 1995), pgs. 88-96. And see: M. Michael
Glovsky and others, "Can Latex Allergy be Triggered by Air Pollution?"
Abstract presented at Experimental Biology '95 in Atlanta, Georgia
during April, 1995. Dr. Glovsky's address: Asthma Center, Huntington
Memorial Hospital, Pasadena, CA 91105. Phone: (818) 397-3383; fax:
(818) 795-0982. Glovsky's work is discussed briefly in J. Raloff,
"Latex allergies from right out of thin air?" SCIENCE NEWS Vol. 147,
No. 16 (April 22, 1995), pg. 244. See also: L.M. Hildemann and others,
"Chemical Composition of Emissions from Urban Sources of Fine Organic
Aerosol," ENVIRONMENTAL SCIENCE & TECHNOLOGY Vol. 25, No. 4 (1991),
pgs. 744-759.

[4] Doris Jaeger and others, "Latex-Specific proteins causing
immediate-type cutaneous, nasal, bronchial, and systemic reactions,"
pgs. 759-768. And: Gordon L. Sussman and Donald H. Beezhold, "Allergy
to Latex Rubber," ANNALS OF INTERNAL MEDICINE Vol. 122, No. 1 (January
1, 1995), pgs. 43-46. And: Denise-Anne Moneret-Vautrin and others,
"Prospective study of risk factors in natural rubber latex
No. 5 (November 1993), pgs. 668-677.

[5] Tire use in 1995 is a projection based on trends from 1970-1990
shown in: Bureau of the Census, U.S. Department of Commerce,
Government Printing Office, 1990), Table 1027; and Bureau of the
Census, U.S. Department of Commerce, Statistical Abstract of the United
States 1992 (Washington, DC: U.S. Government Printing Office, 1992),
Table 1000.

[6] Richard Lipkin, "No-itch latex," SCIENCE NEWS Vol. 147, No. 16
(April 22, 1995), pg. 254.

[7] C. Arden Pope III and others, "Particulate Air Pollution as a
Predictor of Mortality in a Prospective Study of U.S. Adults," AMERICAN
(March 1995), pgs. 669-674. See also REHW #373.

Descriptor terms: automobiles; transportation; mass transit; railroads;
trolleys; electric street railways; firestone; gm; standard oil of
california; new york, ny; philadelphia, pa; baltimore, md; st louis,
mo; oakland, ca; salt lake city, ut; los angeles, ca; pacific electric
railway; diesel; buses; global warming; lung cancer; asthma; allergies;
latex allergy; rubber; guayule plant; air pollution; radial tires; fine
particles; bias ply tires;

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