Charles
V. Schwab, Mark Hanna and Laura
Miller
Iowa State University Extension
Despite
attention in recent years to laws regarding its transport,
application, and storage, anhydrous ammonia remains a serious
health risk for Iowa farmers. According to the Iowa Department
of Public Health, 55 Iowans were injured in accidents involving
anhydrous ammonia between 1990 and 1992. Nineteen injuries
required hospitalization for burns, loss of eyesight, and
respiratory problems.
This
publication will look at common ways Iowans are exposed to
anhydrous ammonia and how to avoid these situations, its properties
and first aid treatment, as well as Iowa regulations regarding
its transport.
Exposure
to anhydrous ammonia can happen suddenly and is almost always
unexpected, including these situations:
- During
its transfer from the nurse tank to the applicator. Anhydrous
ammonia can escape from the transfer hose or valves that
connect the hose to the nurse tank or applicator. Farm operators
must always follow procedures for making and breaking connections
because the fertilizer is under extreme pressure.
- When
equipment fails. Malfunctions of valves, the quick coupler
that connects the nurse tank to toolbar, and gauges cause
dangerous situations that could spray anhydrous ammonia
in any direction with a force greater than that of a fire
hydrant. Hoses exposed to sunlight, constant rubbing, or
those that are stretched are subject to failure.
- During
transportation or application in the field. A loose or broken
hitch can cause the anhydrous hose to simply pull apart.
Always use safety chains and a locking hitch pin when transporting
the nurse tank.
Anhydrous
ammonia is a hydroscopic compound, which means that it seeks
water from the nearest source, including the human body. This
attraction places the eyes, lungs, and skin at greatest risk
because of their high moisture content. Caustic burns result
when the anhydrous ammonia dissolves into body tissue.
Most
deaths from anhydrous ammonia are caused by severe damage
to the throat and lungs from a direct blast to the face. When
large amounts are inhaled, the throat swells shut and victims
suffocate. Exposure to vapors or liquid also can cause blindness.
An additional
concern is the low boiling point of anhydrous ammonia. The
chemical freezes on contact at room temperature. It will cause
burns similar to, but more severe than, those caused by dry
ice.
Under
normal temperature and air pressure, anhydrous ammonia is
a colorless gas. However, anhydrous ammonia is used and transported
under pressure as a liquid. All equipment used for applying
or transferring liquid anhydrous ammonia must be designed
for use under high pressure to avoid ruptures or breaks.
Anhydrous
ammonia has a distinct odor, which humans can detect in concentrations
as small as 5 parts per million (ppm). When used in fertilizer,
anhydrous ammonia has a concentration of about 1,000,000 ppm.
Brief exposure to concentrations of 2,500 to 6,500 ppm can
result in death.
The
best ways to reduce risk of serious injury from anhydrous ammonia
exposure are to wear protective equipment and to know what to
do in an emergency.
Always
wear ventless goggles or a full-face shield, rubber gloves
with a long cuff that can be rolled to catch drips, and a
long-sleeved shirt. Non-rubber gloves made of ammonia-proof
materials also are acceptable. Never wear contact lenses around
anhydrous ammonia because the lenses collect the chemical
and intensify caustic effects.
Always
carry a personal water supply in a squeeze bottle to use for
instant first aid. The bottle should contain 6 to 8 ounces
of clean water and be within arm's reach at all times. At
least five gallons of water should be accessible within several
seconds.
The
best first aid treatment for anhydrous ammonia exposure is
water -- large amounts of it. Flush all exposed areas with
water for at least 15 minutes.
If the
nose or throat is exposed, flood the area repeatedly for 15
minutes, being careful not to choke the victim. Even a brief
or mild exposure to the eyes requires irrigation for a minimum
of 15 minutes. Remember to flush underneath eyelids.
Always
begin flushing immediately. This reduces injuries, caused
as soon as anhydrous ammonia contacts skin or clothes. If
water is not immediately available, use any non-toxic liquid
such as cold coffee. Orange juice and other mildly acidic
liquids will help neutralize the chemical. Water from a nearby
farm pond also can be used until other water supplies are
available.
Even
with proper first aid, seek medical help as soon as possible.
Explain the source of the injury so that medical providers
will not apply oils or ointments. This treatment intensifies
damage from burns.
If you
find someone in a continuous stream of anhydrous ammonia,
do not attempt rescue without proper equipment. Rescuers must
wear a self-contained breathing apparatus (SCBA) and protective
clothing.
Always
take care in removing a victim's clothing. Clothes could be
frozen to the skin and removal could cause additional injury.
Iowa
Code restricts towing of anhydrous ammonia nurse tanks to not
more than three vehicles (including the truck or tractor) for
a maximum length of 60 feet. The Code also requires safety chains
and that the vehicle operator stop at all railroad crossings.
You
also must display the slow-moving vehicle (SMV) emblem if
you're traveling at speeds less than 25 miles per hour. At
higher speeds, remove or cover the emblem. In Iowa, speed
limits are determined by the rating marked on the nurse tank
tires.
It's
important to understand the dangers of anhydrous ammonia.
Operators should know and understand all procedures, usually
provided by the chemical dealer, before they begin anhydrous
ammonia application. Better yet, operators may want to consider
hiring a professional to perform this dangerous job.
How
Much Do You Know?
- The
effects of anhydrous ammonia exposure to humans can be best
described as a:
- poison.
- antiseptic.
- corrosive
agent.
- cleaner.
- Anhydrous
ammonia is a hydroscopic compound, which means it seeks
out moisture. True or false?
- During
spring weather and under normal atmospheric pressure, anhydrous
ammonia is a liquid. True or false?
- Contact
lenses offer some eye protection from anhydrous ammonia
exposure. True or false?
- What
liquid can you use for first aid treatment in anhydrous
ammonia exposure?
- orange
juice
- water
- cold
coffee
See
answers at the end of "What Can You Do?".
What
Can You Do?
You can
reduce your risk of exposure and reduce injuries in these ways:
- Always
keep 5 gallons of clean water in your supply tank and carry
a small squeeze bottle.
- Understand
first aid treatment and practice what you would do in an
emergency.
- Wear
ventless goggles, rubber gloves, and a long-sleeved shirt
when working with anhydrous ammonia.
- Regularly
inspect equipment and have worn hoses and valves replaced.
- Never
allow bystanders in the area where anhydrous ammonia is
being transferred or applied.
- Review
instructions before coupling and uncoupling lines.
Answers
to quiz:
1-c;
2-True; 3-False; 4-False; 5-a, b, and c.
- For
more detail about regulations regarding transportation,
contact the Iowa Department of Transportation Motor Vehicle
Enforcement Division by calling, toll-free,1-800-925-6469.
- For
information regarding the chemical properties of anhydrous
ammonia, contact the Technical Information Service at the
National Institute for Occupational Safety and Health (NIOSH)
by calling, toll-free, 1-800-35-NIOSH.
- For
The National Safety Council Rural Accident Prevention
Bulletin: Handling Anhydrous Ammonia Safely, in Iowa
call toll-free, 1-800-776-6724. There is a fee for the publication.
Disclaimer
and Reproduction Information: Information in NASD does not
represent NIOSH policy. Information included in NASD appears
by permission of the author and/or copyright holder. More
NASD Review: 04/2002
This
document is Fact Sheet
Pm-1518d
,
a series of the Safe Farm Program, Iowa State University Extension,
Ames, Iowa. Safe Farm promotes health and safety in agriculture.
It is funded by the National Institute for Occupational Safety
and Health, Iowa State University, and a network of groups
that serve Iowa farm workers and their families. Publication
date: April 1993.
Prepared
by Charles V. Schwab, extension safety specialist; Mark Hanna,
extension agricultural engineer, and Laura Miller, extension
communications, Iowa State University Extension, Ames, Iowa
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