In the course of researching polystyrene foam insulation, the Healthy Building Network research team came to understand that these materials are susceptible to termite infestation. Polystyrene insulation manufacturers commonly add insecticides to combat termites, especially in exterior and below grade insulation. This includes a type of Styrofoam made by the dominant manufacturer, Dow Chemical.
This article is intended as a warning to beekeepers who are considering building “nucs” — the boxes that house nucleus colonies — with polystyrene foam insulation. These boards may contain insecticides that are toxic to bees.
Pesticides commonly used in polystyrene insulation include imidacloprid and deltamethrin.
Imidacloprid is a member of a class of insecticides called neonicotinoids, which cause “sublethal” effects on bees – by not killing them directly, but weakening them. The honeybees become more susceptible to death by other pesticides or by disease. (1) Neonicotinoids are believed to contribute to Colony Collapse Disorder. (2) Deltramethrin is a synthetic pyrethroid, which Beyond Pesticides describes as a class of chemicals that have “been shown to impair bee learning and foraging behavior.” (3)
Not all polystyrene foam insulation boards contain these insecticides, but many do. The HBN research team identified several Expanded Polystyrene (EPS) foam insulation boards that contain imidacloprid. (4) And Dow Chemicals makes an Extruded Polystyrene (XPS) foam insulation board called Styrofoam Blueguard™, used in foundations where there is a termite infestation, that contains deltamethrin. (5)
Alarmingly, it turns out that one of the favored materials used by beekeepers is polystyrene insulation board. Beekeeping forums are filled with discussions and examples of using it to build nuc boxes. (6)
We urge beekeepers to ask polystyrene manufacturers for definitive answers about whether their boards contain any insecticides, before using EPS or XPS to build nuc boxes. The answers may not be found in Material Safety Data Sheets or other product literature. By asking the right questions we can keep any building, including bees’ homes, free of materials that are hazardous to the occupants’ health.
 Dively, G. P., et. al. (2014). "Assessment of chronic sublethal effects of imidacloprid on honey bee colony health." PloS one, 10(3), e0118748-e0118748. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0118748;
EPA. "Pesticide News Story: EPA Issues Registration Review Final Work Plan for Imidacloprid." Press release, July 13, 2009. http://www.epa.gov/oppfead1/cb/csb_page/updates/2009/imidacloprid.html;
Darriet, F., & Chandre, F. (2013). "Efficacy of six neonicotinoid insecticides alone and in combination with deltamethrin and piperonyl butoxide against pyrethroid‐resistant Aedes aegypti and Anopheles gambiae (Diptera: Culicidae)." Pest management science, 69(8), 905-910. http://www.ncbi.nlm.nih.gov/pubmed/23208775;
Dai, P. L., et. al. (2010). "Effects of sublethal concentrations of bifenthrin and deltamethrin on fecundity, growth, and development of the honeybee Apis mellifera ligustica." Environmental Toxicology and Chemistry, 29(3), 644-649. http://www.ncbi.nlm.nih.gov/pubmed/20821489;
Cohnstaedt, L. W., & Allan, S. A. (2011). "Effects of sublethal pyrethroid exposure on the host‐seeking behavior of female mosquitoes." Journal of Vector Ecology, 36(2), 395-403. http://naldc.nal.usda.gov/download/55704/PDF
 EPA. "Colony Collapse Disorder: European Bans on Neonicotinoid Pesticides." Last updated August 15, 2013. http://www.epa.gov/pesticides/about/intheworks/ccd-european-ban.html
 Beyond Pesticides. http://www.beyondpesticides.org/pollinators/chemicals.php
 LOGIX Insulated Concrete Forms. "Logix TX: First Line Of Defense Against Termite Attacks." December 2010. http://logixicf.com/media/library/documents/Tech%20Bulletin%2024%20011911%20-%20Logix%20TX4d377c9527e87.pdf;
US Patent & Trademark Office, decision on Lanxess Corporation patent appeal. January 27, 2015. http://e-foia.uspto.gov/Foia/RetrievePdf?system=BPAI&flNm=fd2013009662-01-23-2015-1;
Cellofoam. "Cellofoam Insect Resistant Rigid Insulation." http://colonialgreenproducts.com/eps_insect_resistant.pdf
 Dow Chemical. "Styrofoam Blueguard™ Extruded Polystyrene Insulation." http://inlineco.com/msds/Dow_Corning/http___www.dow.com_PublishedLiterature_dh_006d_0901b8038006d55c.pdf_filepath=styrofoam_pdfs_noreg_179-07348.pdf
 See, for example, Alaska Honey Bee, "Nuc Boxes" http://alaskahoneybee.com/bee-links-and-resources/nuc-boxes/; and Honey Bee World, "Styrofoam Boxes" [online forum thread] http://www.honeybeeworld.com/forum/viewtopic.php?t=217