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#82 - Incineration Of Infectious Waste, 19-Jun-1988

In 1985, there were 6872 hospitals in the U.S. with 1.3 million beds.
If beds are occupied 70% of the time and each occupied bed creates 13
pounds of waste per day, U.S. hospitals produce 2.2 million tons of
waste per year. An estimated 15% of this is infectious waste containing
human anatomical waste, plus garments, gauze pads, diapers, catheters,
and so forth. But the infectious 15% cannot be segregated from the non-
infectious, so it all gets mixed together, creating a larger mass that
must all be considered infectious.

An estimated 90% of all hospitals run their own incinerators; this
means about 6,200 neighborhoods are impacted by such machines. From the
viewpoint of people living near hospitals, there are five items of
concern: (1) the emission of bacteria or viruses that might make people
sick; (2) the emission of low molecular weight organic molecules
(trichloroethylene [a suspected carcinogen], and tetrachloroethylene,
among others); (3) the emission of high molecular weight organic
molecules, (so called "products of incomplete combustion,"
benzopyrenes, PCBs, polynuclear aromatic hydrocarbons and other
polycyclic organic matter, much of which is carcinogenic); (4) the
emission of toxic particles small enough for a person to breathe deep
into their lungs; (5) and the emission of dioxins and furans.

The U.S. Environmental Protection Agency (EPA) recently released a
report completed under contract by the Radian Corporation. The aim was
to gather what is known about pollution from hospital incinerators. The
authors searched the scientific literature, and interviewed many
knowledgeable experts: staff of regulatory agencies (EPA, state and
local), the American Hospital Association, and incinerator vendors.

Of the estimated 6200 hospital incinerators in use, perhaps 1200 are
large incinerators (burning more than 400 pounds per hour or 400 tons
per year) and 5000 are smaller. Hospital incinerators fall into three
types: rotary kiln, excess air and starved air. By far the commonest
(especially among units installed during the last 15 years) is starved
air (also called "controlled air," "two-stage" and "modular"). Excess
air incinerators (also called "pyrolitic incinerators," and "multi-
chamber incinerators") come in two types: large units, which are
generally "in-line," and smaller units, which are generally "retort"
types.

Radian could find no air emissions data for small excess-air
incinerators, the kind that serve perhaps 75% or more of the nation's
hospitals. Therefore, the remainder of this article describes air
emissions from large controlled-air incinerators.

Even among these few incinerators, the lack of data is shocking. Let's
look at the five categories mentioned above.

BACTERIA AND VIRUSES. You might think emission of disease-causing
organisms (pathogens) from hospital incinerators would be the subject
of intense scrutiny. Not so. The Radian corporation could find only two
studies in the scientific literature. One study found twice as many
bacteria leaving an incinerator smoke stack as were found in normal
outdoor air (though the results were not statistically significant; in
other words, they may have occurred by chance). The second study showed
that, in a two-chamber incinerator, the temperature in the first
chamber has to be 1400 degrees Fahrenheit and in the second chamber had
to be 1600 deg. F. to guarantee sterilization of bacteria and viruses.
(Many incinerators are not designed to exceed 1400 deg. in their
secondary chamber, so presumably do not effectively sterilize wastes
they burn.) That ends the discussion of bacteria and viruses in the
Radian study. The entire section on pathogens takes up 14 lines of text
in a 151-page report.

LOW MOLECULAR WEIGHT ORGANIC COMPOUNDS: Radian says, "One large data
gap in the current hospital waste incinerator emissions data base is
for lower molecular weight organic compounds." End of discussion.

PRODUCTS OF INCOMPLETE COMBUSTION, BENZOPYRENE, PCBS AND OTHER
CARCINOGENIC ORGANIC MOLECULES: These pollutants are "important," says
Radian, but are not included in the study "due to lack of emissions
data."

TINY TOXIC particles: A micron is a millionth of a meter (and a meter
is about a yard). If you breathe particles (soot) in the size range of
2 to 10 microns in diameter, they are filtered out by the respiratory
system (nose, esophagus, etc.) and are moved into the mouth, then
swallowed. Particles smaller than 2 microns are considered "respirable"
because they can enter the deep lungs. The smallest particles (1 micron
or less) enter the deepest part of the lung, the alveoli, the 3 million
little sacs that pass oxygen into the blood and let carbon dioxide pass
back out. Particles that enter the alveoli may eventually be removed by
natural cleansing mechanisms, or they may lodge there, contributing a
grey color to the normallypink lungs, or they may actually pass into
the blood stream and go someplace else in the body.

As luck would have it, the respirable particles from an incinerator
contain more than their fair share of toxic materials, especially toxic
metals and the oftencarcinogenic polycyclic organic molecules. The
small particles have a larger surface area in relation to their bulk
than do larger particles. (A physicist would say small particles have a
larger surface-to volume ratio.) The relatively large surface area of
the smallest particles attracts toxic heavy metals during combustion.
Thus, respirable particles end up LOADED (Radian says "enriched") with
lead, arsenic, cadmium, chromium and other dangerous metals. (Radian
presents no data on enrichment by polycyclic organics, unfortunately.)
Thus the particles that reach deepest into the lungs are the most
toxic. Typical hospital incinerators emit 1.5 to 36 pounds of particles
per ton of waste incinerated. (Incidentally, bacteria and viruses have
diameters ranging from 0.4 microns down to 0.02 microns, so they are
definitely respirable.)

DIOXINS AND FURANS: The Radian study describes in detail the combustion
conditions under which dioxins and furans will be formed. They conclude
that the primary chamber of a hospital incinerator is PERFECT for
manufacturing dioxins and furans, and that safety depends upon the
secondary chamber completely destroying the dioxins by maintaining
ideal combustion conditions. They conclude that the average amount of
total dioxins emitted from a 1000 poundper-hour hospital incinerator
operating 2000 hours per year would be 3.7 grams of dioxin per year.
(There are 28 grams in an ounce.) This may not sound like much, but
dioxin is considered extremely toxic, so it may be a lot, depending on
where it goes once it is released into your neighborhood.

Conclusion: The nation's primary medical care institutions are almost
all operating incinerators without knowing what they are doing,
literally. The data are simply not available. What data there are, on
respirable particles and dioxins, indicate the need for very tight air
pollution control, which is not provided under federal law, nor under
most state laws. In short, hospital incineration of infectious wastes
is a scandal.

To get your free copy of Radian's HOSPITAL WASTE COMBUSTION STUDY, DATA
GATHERING PHASE, FINAL DRAFT REPORT, write Ray Morrison, Pollutant
Assessment Branch, Office of Air Quality Planning and Standards, EPA,
Research Triangle, NC 27711; phone (919) 541-5332.

--Peter Montague

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Descriptor terms: incineration; medical waste; carcinogens;
trichloroethylene; pcbs; benzopyrenes; pahs; hydrocarbons;
particulates; dioxin; pcdfs; epa; lung cancer; american hospital
association; rotary kilns; starved air kilns; excess air kilns; radian
corp; bacteria; viruses; air; air pollution; air quality; studies;
findings;