=======================Electronic Edition========================
RACHEL’S ENVIRONMENT & HEALTH WEEKLY #439
—April 27, 1995—
News and resources for environmental justice.
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TIRE DUST
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 RHWN #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, 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 6.5 pounds (3 kilograms) of dust
released from each tire each year. In 1995, there were an
estimated 280 million tires in use in the U.S.; [5]if each tire
releases 6.5 pounds of dust per year, tire dust released in 1995
would total 1.8 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
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[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 RHWN #120.
[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 JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE Vol.
151, No. 3 (March 1995), pgs. 669-674. See also RHWN #373.
Descriptor terms: automobiles; transportation systems; general
motors; mass transit; railroads; trolleys; electric street
railways; firestone rubber; gm; standard oil of california; new
york; philadelphia; baltimore; st. louis; oakland; salt lake
city; los angeles; pacific electric railway; diesel; buses;
global warming; lung cancer; asthma; allergies; latex allergy;
rubber; guayule; air pollution; radial tires; fine particles;
bias ply tires;