To All Members of MuseumPests.Net - A recent inquiry came into the website from John Simmons about a photograph of a very old Vapona resin strip found in a museum. The carboard enclosure was stained at the bottom; someone attributed this to phosphoric acid. Allow me to set the record straight:
In 1948, the Shell Chemical Company obtained a patent for dichlorvos (DDVP, Vapona), number 2,956,073. Later a patent was also obtained for techical grade Vapona. The Shell No-Pest Strip was introduced in 1963. This strip had problems with "bleeding" attributed to the plasticizer formulation in the strip; hence the one found by Mr. Simmons is probably at least 50-years old. The stains were from the leaking plasticizers in this strip. Subsequently, sometime after 1963, the Texize Corporation bought the rights to the No-Pest Strip from Shell, reformulated it, and produced a resin strip which did not bleed. This modified polyvinyl chloride strip was DDVP (2,2-Dichlorovinyl dimethyl Phosphate) and was given patent number 3,769,416. This strip was labeled for use in enclosed spaces at a rate of 1 strip per 1,000 cubic feet of space for all sorts of insects. The strip, when first introduced into a space, generates dichlorvos in about a week and a half at 120 parts per trillion in the ambient air. From this point, the strip gradually loses its generating power to 80 ppt at week 4; 56 ppt at week 8, 37 ppt at week 12; and approximately 20 ppt at week 16. Any amount in excess of approximately 10 ppt will kill insects. A Texize No-Pest Strip therefore was effective for 4 months. On February 12, 1988, the EPA issued Dichlorvos; Notice of Initiation of Special Review. As a basis for this review, the EPA scientists produced a scenario of a 70 kg individual breathing DDVP vapors for a 16 hour day. Their calculations were way overstated, based on the amount a resin strip was capable of producing. What they really were concerned with was the use of DDVP liquid and fogging formulations used industrially. In response to the EPA request for comments from the general public, I submitted a lengthy letter with citations in attempt to illustrate how their calculations were way over-stated. I was attempting to save the resin strip for use in artifact and specimen protection against pests in museums under certain situations. The amount generated by a resin strip simply didn't match the EPA's theoretical calculations of inhalation dosage for humans. In the Spring of 1989, in the Textile Conservation News Letter, Sharon Hammick gave a scathing report of the toxic effects of DDVP. Unfortunately she confused the techican grade DDVP to what a resin strip could produce. At the time, Canada, where she works, did not have the non-bleeding type resin strip, and therefore her conclusions were not based on what was available in the United States from the Texize Corporation. In 1990, the EPA, which originally classified DDVP as a B-2 probable carcinogen, downgraded this pesticide to a class C designation; a possible carcinogen. Even with the downgrade, the EPA, in November, 1993 revoked the registration of DDVP for any use in the United States. A long battle between Amvac Corporation, the current holder of the patents for the resin strip, and the EPA ensued. In the interim, I sent several detailed letters to EPA in support of the use of resin strips for the protection of museum collections, basically stating the controlled release of minute amounts of DDVP into the ambient air was way below the level considered harmful to humans. In addition, the human body readily detoxifies DDVP to the point where researchers find it difficult to run tests on humans with this compound. Finally EPA has now seen the resin strip, if properly used in museums, not to be a threat to human health. In the last few years, Amvac Corporation has re-introduced the resin strip to our museum community with EPA Registration Number 5481-96, which is now called the Nuvan strip. It is available in a variety of different sizes and is labeled for museum use. There are restrictions on the labels as to how long an individual can occupy a space, which is being treated. In certain situations, there are no restrictions. My rule of thumb, if an infestation must be knocked out in a confined space, introduce the strip or strips (depending on the cubic footage) for no more than three weeks. Within that time, every form of insect life will be killed. This short period of time should have no ill effects on artifacts or specimens. Do not simply put strips in cases and forget about them. Hang the strips high because the DDVP is a bit heavier than air. If the room is heated above room temperature, the time can be reduced somewhat. These strips are quite effective against carpet beetle, silverfish, and webbing clothes moth infestations. Note: In certain situations, the professional pest management industry uses Nuvan strips for bed bug control. I hope this message has given you all insight about the history of the "Shell" No-Pest Strip and its reintroduction as Nuvan resin strips into the marketplace for specific use in museums. Thomas A. Parker, PhD President, Entomologist Pest Control Services, Inc. 469 Mimosa Circle Kennett Square, PA 19348 610-444-2277 www.museumpestcontrol.com -----Original Message----- From: Del Re, Christine <de...@mpm.edu> To: pestlist <pestlist@museumpests.net> Sent: Tue, Feb 1, 2011 2:53 pm Subject: RE: [pestlist] ID of pesticide package Agreed. That is an old DDVP pest strip – we still have some buried in our rather inaccessible light fixtures here………………. From: pestlist-ow...@museumpests.net [mailto:pestlist-ow...@museumpests.net] On Behalf Of bugma...@aol.com Sent: Tuesday, February 01, 2011 1:50 PM To: pestlist@museumpests.net Subject: Re: [pestlist] ID of pesticide package John - >From the stains at the bottom of the white cardboard, it appears to be an old >DDVP (Vapona) resin strip in an enclosure. It's very old and no longer >volatilizing the pesticide, dichlorvos, into the air. It can be safely >discarded into the regular trash. Thomas A. Parker, PhD President, Entomologist Pest Control Services, Inc. -----Original Message----- From: John E Simmons <simmons.jo...@gmail.com> To: pestlist <pestlist@museumpests.net> Sent: Tue, Feb 1, 2011 2:14 pm Subject: [pestlist] ID of pesticide package Can anyone help identify the pesticide likely to be in the package shown in the attached image? Thanks, John John E. Simmons Museologica 128 E. Burnside Street Bellefonte, Pennsylvania 16823-2010 simmons.jo...@gmail.com 303-681-5708 www.museologica.com and Adjunct Curator of Collections Earth and Mineral Science Museum & Art Gallery Penn State University University Park, Pennsylvania
