Residual Pesticides


Before the invention of environmentally controlled museum spaces and integrated pest management techniques, museums commonly relied on pesticides to prevent pest infestation and damage. Natural history museums often contain extensive organic collections (e.g. taxidermy and entomology specimens, and study skins) and are especially vulnerable to pest activity. Pesticides have been used by museum staff since the late 18th century and some may still be in use. Some of the most common pesticides found in collections are:

  • Arsenic – both powered and liquid arsenic, also known as arsenic soap, were especially prevalent in taxidermy preservation
  • Mercury – also known as mercuric chloride or corrosive sublimate was commonly used on botanical specimens
  • Napthalene – in either flake or ball form remains in use, most commonly known as ‘mothballs’
  • Paradichlorobenze (PDB) – in either cake or crystal form also remains in use, commonly known as ‘mothballs’
  • Dichloro-diphenyl-trichloroethane (DDT) – from the 1940-70s DDT was sometimes applied as a pesticide or disinfectant to biological and animal specimens as well as library materials.

These chemicals and compounds were applied in a variety of ways:

  • brushing or rubbing onto the object
  • submersion
  • fumigating a storage or exhibit area

These materials were potent and easy to acquire and some, such as mothballs, are still obtainable today. Although these contaminants are highly effective at killing insects, such as clothes moths and carpet beetles, they do not discriminate between pests and humans. Staff members working with objects or in museum spaces that have been treated with pesticides are at risk of contaminating themselves through chronic and/or acute exposure.For this reason none of the materials listed above are approved for current use in museum collections and their use is now considered inappropriate and illegal.

Commonly Treated Items

Specimens in Mammalogy and Ornithology (taxidermy specimens, animal skins/hides, bone), botany (all plant material, including seeds), entomology, as well as storage cabinets and exhibition spaces.


There are several ways in which museum staff can and should investigate the history of pesticide use in their collections:

  • Research museum records. Often clues to pesticide use can be found in acquisition records, museum staff correspondence and, when they exist, early treatment reports. Collectors generally treated all their materials in the same way even if they were supplying specimens to multiple museums. Contact other institutions that might have shared the same staff.
  • Interview staff to discover past preservation practices. The institutional memory of long-time staff members can be rich in information on past practices.
  • Look through your storage areas. There may be old containers or labels that indicate past use of a chemical in the institution.
  • Carefully inspect collection pieces for visible evidence of pesticide use. Although most chemicals leave no residue, arsenic can sometimes be seen on the surface of a specimen as a white powdery substance
  • Spot analysis. Chemical spot tests or analytical techniques such as FTIR can be definitive in identifying the presence of pesticides. (For more on this see the information on the AMNH Conservation Lecture Series April 19. 2009 talk “Pesticide Residues on Museum Objects” by Nancy Odegaard lecture [link to cons series lecture page in the Links & Resources section]


Contamination may occur through inhalation, ingestion, or dermal contact. Symptoms may be acute or chronic and will vary depending on the amount of pesticide introduced into the body. Acute symptoms include irritations and nausea, while chronic symptoms may result in more serious illnesses.


  • Even if records proving pesticide use do not exist, care should always been taken when handling objects or working in collection or exhibition areas, especially if your museum was established, or contains specimens, before 1970. Many of the pesticides do not break down easily, and therefore have a long residual life.
  • Wear appropriate personal protection equipment (PPE) for protection when handling specimens, such as disposable gloves, disposable face mask, safety goggles, and protective clothing like a lab coat or apron.
  • Educate staff on proper handling of taxidermy and possibly-contaminated specimens.
  • Use a fume hood when examining contaminated objects.
  • Wash hands after handling contaminated objects.
  • Eliminate use of residual pesticides in storage areas and display areas.
  • Implement an Integrated Pest Management Plan to prevent infestation so residual pesticides are no longer necessary.
  • If an infestation does occur, use alternative techniques to eliminate pests, such as freezing objects.

Additional Resources

Download information on safe disposal of storage and rehousing materials that may be contaminated by heavy metal pesticides [link to Removal of Hazardous Waste from Collections pdf]

Download information on tips to consider when devising a program for testing and monitoring staff for exposure to heavy metal pesticides [link to tips for devising a testing and monitoring program pdf]

For specifics on arsenic spot testing, access the procedures published in 1996 by the Western Association for Art Conservation [WAAC] Vol: 18:1 []

Tests may also be found in the book Odegaard, Carroll and Zimmt. 2000. Material Characterization Tests for Objects of Art and Archaeology. Archetype Publications. London.

Several of the National Park Service Conserve O Gram leaflets listed in the section on Security, Fire and Curatorial Safety provide specific information on this topic. The online leaflets particular interest on this topic are:

The Society for the Preservation of Natural History Collections' journal, Collection Forum, contains several relevant papers:

  • Caldararo, N., et. al. Eds. 2001. “The Contamination of Museum Materials and the Repatriation Process for Native California.” Proceedings of a Workshop Conference at the San Francisco State University, 2000. Vol. 16, no. 1 & 2.
  • Johnson, J. and J. Bishoff. 2001. “Contaminated Collections: Preservation, Access, Use.” Proceedings of a Retreat at the National Conservation Training Center, West Virginia, 2001. Vol. 17, no. 1 & 2.

Extoxnet- The EXtension TOXicology NETwork for pesticide information for the non-expert

National Pesticide Information Center offers pesticide fact sheets

US Environmental Protection Agency, Office of Pesticide Programs offers a variety of information and regulations by the government on pesticides. Information sections include Health and Safety, Regulating Pesticides, and Environmental Effects

US Poison Control and Prevention Center Directory, provides a search engine to find local poison centers


The references below are specific to the history of pesticide use in museums, but there are other general resources that encompass all the hazards of natural history museums/natural science collections with sections of pesticide use. Please visit this site’s Resources page to access the complete bibliography [link to Resources].

Albrecht, Carl W. 1993. “Arsenic and Old Collections.” In Local History Notebook. March/April. Ohio Historical Society.

Goldberg, Lisa. 1996. “A History of Pest Control Measures in the Anthropology Collections, National Museum of Natural History, Smithsonian Institution.” In Journal of the American Institute for Conservation 35. pp. 23-43.

Marte, Fernando, Amandine Pequignot, and David W. Von Endt. 2006. “Arsenic in Taxidermy Collections: History, Detection, and Management.” In Collection Forum. Vol. 21, no. 1-2. pp. 143-150.

Miller, Patricia L. 1991. "Arsenic, Old Lace, and Stuffed Owls May Be Hazardous to your Health: Hazards in Museum Collections." In Illinois Heritage Association Technical Insert. March/April issue.

Odegaard, Carroll and Zimmt. 2000. Material Characterization Tests for Objects of Art and Archaeology. London: Archetype Publications.

Odegaard, Nancy, et. al. 2005. Old Poisons, New Problems. Walnut Creek, CA: Alta Mira Press.

Odegaard, N., and A. Sadongei. 2000. “Contaminated Cultural Materials in Museum Collections: Reflections and Recommendations for a NAGPRA Issue.” In the Western Association of Art Conservation Newsletter. Vol. 22, no. 2.

Ogden, Sherelyn, Ed. 2004. Caring for American Indian Objects. Minnesota Historical Society Press.

Reigart, Dr. J. Routt, and Dr. James R. Roberts, Eds. 1999. Recognition and Management of Pesticide Poisonings. US Environmental Protection Agency.