RCC Alerts
Contents
Sulfonylurea Herbicide Alert
Heat-Generated PTFE Fumes:A Silent Killer of Birds In Our Care
Sulfonylurea Herbicide Alert
An incident in Idaho
In mid-2001, farmers in south-central Idaho suffered significant damage to their sugar beet and potato crops. They attributed the problem to the sulfonylurea herbicide, sulfometuron methyl that had been applied to approximately 17,000 acres of land adjacent to their fields. This land had been scorched by wildfire in August 2000.
The herbicide, applied in October 2000, was intended to prevent cheat grass, an undesirable invasive, from growing
on the burned-out land. At the time, the weather had been very dry, and soil was seen blowing from the site after
the herbicide application.
Sulfometuron methyl, a very potent, broad-spectrum herbicide is registered for use along roadsides, in rights-of-way,
and in forested areas. Since it is very powerful, application rates are low.
An assay method exists for detecting sulfometuron methyl, and thus the "Idaho Department of Agriculture
was able to determine that [the ingredient sulfometuron methyl]" was indeed present in the damaged potato
and sugar beet fields (Twin Falls Idaho Times News, June 6, 2001).
Thousands of acres of sugar beets and potatoes in Idaho appear to have been adversely affected by the herbicide
drift with losses to farmers estimated to be as much as $1 billion (per the online Twin Falls Idaho Times News,
June 27, 2000 ).
Our concerns
This unhappy situation leads us to pose the following questions (and some answers):
How long could the south-central Idaho soil that has been contaminated with sulfometuron-methyl remain hazardous for crops and other vegetation?
Could sulfometuron-methyl be legally used in similar situations?
Could a labeling statement have prevented such use? Such a statement could be as follows: "Do not apply where treated soils can be moved by washing or blowing onto cropland" (p. 143, Agricultural Chemicals Book II, Herbicides, Thompson, 1993).
Are there any plans to add precautions to the sulfometuron labeling in order to prevent future similar situations? If there is not such a statement on it now, we recommend that one be added as soon as possible.
Did the EPA evaluation of costs and benefits of sulfometuron-methyl consider the possibility of such an incident? If not, we recommend that the cost benefit ratio be reconsidered.
As described in the "Plants and Pesticides" manuscript in the proceedings from the RCC Wildlife, Pesticides, and People Conference by Petrie, Schneider and Czerkowicz :
Following grower complaints of yield losses in cherry and apricot orchards downwind from wheat fields treated with chlorsulfuron, a sulfonylurea herbicide, the EPA conducted limited tests on cherry trees and chlorsulfuron.
Reduced cherry yields were observed the year following the application of chlorsulfuron at 1/500 the label rate...a 1/10,000th dilution of chlorsulfuron sulfonylurea label dosage resulted in the inhibition of seed production in crop plants... (p.12)
Wild cherry trees are listed among the top
5 woody plants of importance to wildlife, serving as sources of nectar and food, shade, and erosion control. Damage
to wildlife habitat is less immediately visible to humans than on commercial crops, but the effect is immediate
and long-lasting for the birds, bees, animals, and other creatures who depend on the nectar, leaves, and berries
for survival.
Our intent in looking at such incidents in hindsight is not to assign blame, but rather to bring the incident to light in order to protect our farmers and wildlife populations from future occurrences of the unintended consequences of herbicide applications.
For more information on sulfonylurea herbicides, please contact the Council.
Heat-Generated PTFE Fumes: A Silent Killer of Birds In Our Care
Without warning or visible vapor in homes, zoos, and wildlife rehabilitation facilities
Informed Action Can Prevent Tragic Deaths
PTFE coatings are sold under the trade names
Teflon, Silverstone, Fluoron, Supra, Excalibar, Greblon, Xylon, and others
From Coal Mines to Kitchens
On Saturday, November 12, 2000, Ron, the owner of eight pet birds, started the self-cleaning oven cycle in 
preparation for Thanksgiving dinner. His windows
were open, in compliance with the oven directions. Two hours later, his son noticed that one of the birds was having
trouble standing (all birds were located in a separate room off the kitchen). Four of the birds died quickly in
Ron's hands before anything could be done. Opening more windows saved the other birds.
Microscopic lung findings were consistent with the inhalation of toxic chemical fumes. No warnings about release
of a toxic gas were found in the oven's directions, but the source of the fumes was the oven's nonstick coating
based on PTFE. Confirmed by a necropsy examination, these four pet bird fatalities resulted from normal operation
of the cleaning cycle of this PTFE-coated oven (Ramelmeier & Davidson).
With their sensitive respiratory systems, birds have been used to protect us by detecting poison gas since early
in the industrial age - the legendary canaries in the coal mines (and in the trenches of World War I) - frequently
with lethal outcomes for the birds themselves. Now it is our turn to protect them from a modern hazard.
Those who care for birds need to know about Polytetrafluoroethylene (PTFE) poisoning - the most commonly reported
inhalant toxicity in avians (LaBonde).
Fatalities in birds have occurred when PTFE fumes are emitted by self-cleaning ovens, coated cookware, coated
baking sheets, newly developed coated light bulbs, coated heat lamps, etc. In protecting birds, we may be protecting
ourselves as well. Although much less vulnerable, people also have been poisoned by PTFE fumes (Lee).
The Danger Is Real
Information on avian PTFE toxicity has been available for more than a quarter century. However, not everyone living or working with birds is either aware of heat-generated PTFE toxicity or of which commonly used products could be potential sources of the fumes.
Sadly, many household items capable of generating PTFE fumes do not carry sufficient identifying information,
and most have virtually no warnings about the hazards they represent for birds (Forbes & Jones). Yet
apparently in 1997 a spokesperson from the major PTFE manufacturer acknowledged that fumes from overheated nonstick
coatings could be deadly to birds (European Chemical News).
Toxicity in Birds
When PTFE-coated surfaces are heated above 260 degrees C (400 degrees F), toxic products are released that can
kill a bird in minutes (LaBonde, Forbes & Jones). In most high exposure cases, onset of death occurs
rapidly with no chance for successful medical intervention.
In cases of lower
exposure, eye blinking, panting, and anxiety may be seen. Birds showing these signs will also perish, if not moved
to fresh air immediately. Symptoms can be gasping, staying on cage floor, collapsing, and death.
"Extreme levels of fumes may lead to acute deaths of all birds in the air space immediately. In contrast,
low levels can lead to intermittent deaths of birds within a group over a period of weeks or months" (Forbes
& Jones). A necropsy can help confirm the cause of death as PTFE fumes.
Toxicity in Humans
People affected by heated PTFE may show a well-described illness called Polymer-fume Fever, a flu-like disease
with temporary symptoms. Rarely, it may lead to breathing difficulties requiring emergency treatment (Lee).
Environmental Hazards?
PTFE is used in a variety of products including cookware because it is not easily broken down. At or above 260
degrees C it forms various byproducts including TFA (trifluoroacetate), a persistent chemical thought to have the
potential for environmental problems (Ellis et al.).
The environmental impact of PTFE use has not been well investigated. Scientists have called for more research
on impacts of TFA and other PTFE byproducts.
Could This Happen to Birds In Your Care?
In addition to the tragic outcome suffered by Ron's pet birds following use of a self-cleaning oven, other PTFE-coated products have been linked to avian deaths.
A PTFE-Coated Baking Sheet Hazard
PTFE-coated baking sheets can be dangerous when they come close to a heat source. In one incident, the last bird of a group of four died, "...within 15 minutes of the owner overheating the sides of a baking sheet" (Forbes & Jones).
A Plea for Warnings
"I ... lost my miniature macaw two weeks ago. He died from the toxic fumes [given off] by an overheated...pot. An irreplaceable loss. Please spread the news - not to cook with nonstick cookware...so deadly to birds!!" (Internet communication)
A PTFE Hazard During Rehabilitation
Eight birds of prey died over a period of three months in a facility that was using PTFE-coated heat lamps to warm them overnight. "The lamps appeared to function safely for one year, after which time with continued use at their normal working temperature ... poisonings occurred [due to PTFE]" (Forbes & Jones).
Poultry at Risk from Treated Lights
Fifty-two percent of the chicks in a poultry research facility died within 72 hours after replacement of 48 heat lamp bulbs with PTFE-coated ones. Microscopic lung changes were consistent with PTFE poisoning (Boucher).
|
Historical Note:
The Rachel Carson Connection
References have been found to PTFE's toxicity among Rachel Carson's collected papers, so she very likely was aware
of its potential hazard. During her lifetime, the only reports of PTFE toxicity (or Polymer Fume Fever as it was
called) were from industrial sources and only in humans.
In helping to prevent PTFE-related suffering and death, we at RCC endeavor to continue Rachel Carson's work.
PTFE Scientific & Trade Names
PTFE is a type of plastic or synthetic polymer known as polytetrafluoroethylene or tetrafluoroethylene resin. PTFE
coatings are sold under the trade names:
Teflon, Silverstone, Fluoron, Supra, Excalibar, Greblon, Xylon, and others.
| PTFE may be found in: | |
|
|
|
|
References
Anonymous. European Chemical News, (68) #1779,
1997, p. 26.
Boucher, M., et al. "Polytetrafluoroethylene gas intoxication
in broiler chickens." Avian Diseases, (44) 2000, pp. 449-53.
Ellis, et al. "Thermolysis of fluoropolymers as a potential
source of halogenated organic acids in the environment." Nature,
(412) July 19, 2001.
Forbes, N.A. and D. Jones. PTFE toxicity in birds (letter). Vet Record, (140) #19, May 10, 1997, p. 512.
LaBonde, J. "Pet Avian Toxicology" in 1988 Proceedings, Association of Avian
Veterinarians, pp. 159-173.
Lee, C.H., et al. "Fatal pulmonary oedema after inhalation
of fumes from polytetrafluoroethylene (PTFE)." European Respiratory Journal, (10) 1997, pp.1408-1411.
Ramelmeier, J.L. & J.P. Davidson. "Fatalities in four psittacines, as a result of normal operation of
the cleaning cycle in a polytetrafluoroethylene (PTFE) coated oven." Pesticides,
People and Nature (1) 2003.
Styles, Darrel DVM. "Teflon poisoning: the silent killer." Old World Aviaries (internet source).
RCC Alert
by Drs. Jennifer Ramelmeier and Diana Post
Thanks to Ruth Hanessian, Dr. Greg Harrison, Dr. Stuart Porter, and Donna R. Savage for valuable assistance.
Home // Rachel's Sense of Wonder // Continue Rachel's Work // Sitemap
| PO Box 10779, Silver Spring, Maryland 20914 | |
|
e-mail: rccouncil@aol.com |
Tel: (301) 593-7507 |