Letter from Malinowski, Boulder County
Department of Public Health,
This was sent as an attachment to an e-mail sent
Mr. Malinowski states that the half-life of permethrin is less than 12 hours. He is inaccurate by 5,900 %. Please see the Permethrin Fact Sheet from the National Pesticide Hotline in Appendix II-BB of my website. The half-life of Permethrin in the sunlight is 30 days.
To Whom It May Concern:
Thank you for
The focus of
mosquito control efforts within both unincorporated
If the preferred
methods of mosquito control fail to maintain low mosquito populations, chemical
applications may be used. This includes any emergency spraying for Culex mosquitoes, which transmit West Nile Virus. West Nile
Virus is a serious human health threat. While the disease most often manifests
as a self-resolving fever, for many people the impact of the disease lasts for
months; and for still others, the impacts can be debilitating and lifelong. In
fact, a study of the 2003 Colorado WNV epidemic demonstrated that the infection
caused considerable, long-lasting, severe illness. In 2003,
Mosquito trap data
is one of the main considerations Boulder County Public Health (BCPH) uses when
making the recommendation to spray. There is an extensive network of mosquito
traps located throughout
transmitting WNV, and they are counted and sent to the
When we at BCPH compare the risk of increasing WNV infection in humans with the risk of re-ducing the population of infected mosquitoes using Permethrin (the spray that is applied by a registered applicator strictly following guidelines for use), it is clear which option to choose. The Agency for Toxic Substances and Disease Registry (ATSDR) confirms that Permethrin has been used for many years, with no indication of significant adverse effects on humans when used as recommended.
A walk down any hardware store aisle or a visit to your local greenhouse will reveal a number of insecticides available to the public that are much more toxic than Permethrin. Consumers legally buy and use these other products on their properties at will – independently and without obliga-tion to surrounding residents. An organized, community-based mosquito program, such as the one in Boulder County Mosquito Control District, is much safer than the possible overuse of a broad array of much more toxic chemicals that can be used by individuals.
When used as recommended, Permethrin spray breaks down relatively rapidly in the environ-ment. Sunlight is the major means for breaking down pyrethroids, such as Permethrin. Once exposed to sunlight, the half-life for pyrethroids is less than twelve hours. Pyrethroids are gener-ally considered immobile in soils, and therefore are unlikely to leach into our groundwater. To minimize the impact to open waters, spraying only occurs when wind speed is less than 10 miles per hour.
Residents who do not want their properties to be sprayed have the option of placing their names on the notification or “no spray” list. Individuals on that list are contacted prior to any mosquito-spraying event occurring near their homes. In addition, the community is notified of any spray event in notices that are published in the Boulder Daily Camera and Longmont Times-Call prior to a spray event.
For more information about WNV and its prevention or
detection, or for more detail on mosquito control efforts in
Joe Malinowski Administration/Environmental Health 3450 Broadway Boulder, CO 80304 303-441-1100 Boulder (Sundquist) 3482 Broadway Boulder, CO 80304 303-413-7500 (mailing address: 3450 Broadway) Addiction Recovery Center (ARC) 3470 Broadway Boulder, CO 80304 303-441-1275 (mailing address: 3450 Broadway) Longmont 529 Coffman, Suite 200 Longmont, CO 80501 303-678-6166 Lafayette 1345 Plaza Ct. N., Suite 3A Lafayette, CO 80026 303-666-0515 www.BoulderCountyHealth.org
Consumer Protection Program Coordinator