University of California, Riverside
The Getty Conservation Institute

Michael Rust
Janice M. Kennedy
Frank Lambert
Neville Agnew
Vinod Daniel
Period of Activity: 7/89 to 4/91

Project Abstract
The primary objective of this study was to determine if the displacement of oxygen by gases such as nitrogen, helium, and carbon dioxide is lethal to insects that infest susceptible antiques, artifacts, and objects displayed, curated, or stored in museums. It is possible to produce anoxia and kill these insects. A secondary objective was to expose the insects inside an assortment of items such as books, tapestries, wooden picture frames, etc. in controlled atmosphere chambers to determine if the presence of these objects effect control.

The project consisted of three phases: phase 1-construction and testing of hermetically sealed cases, phase 2-determining the effect of oxygen displacement on various life stages of important insect pests found in museums, and phase 3-testing of artificially infested objects and materials. The objective of phase II was to determine the potential activity of anoxia against insect pests under clinical or ideal conditions. Physical and chemical factors likely to interfere with optimal activity such as the thickness of wood, paper, or cloth were studied in phase III. Seven representative insect pest species were examined in the initial portion of phase II. These are Thermobia domestica (firebrat -Thysanura ), Blattella germanica (German cockroach -Dictyoptera , Periplaneta americana (American cockroach -Dictyoptera ), Incisitermes minor (Western drywood termite -Isoptera , Lasioderma serricorne (Cigarette beetle-Coleoptera), Anthrenus flavipes (Furniture carpet beetle Coleoptera), Tineola bisselliella (Webbing cloths moth-Lepidoptera ).

Phase I of the study was conducted at the Getty Conservation Institute (GCI) and at the University of California, Riverside (UCR). Phases II and III were conducted at UCR because of the large number of insects to be cultured, selected, and observed in each test, the need for controlled temperature chambers to maintain the insect and sealed cases, and the possibility of escape of insects during the rearing and exposure portion of the study.

Primary Publications
Druzik, J. R., M. K. Rust, and J. M. Kennedy, "Pest Control by Oxygen Deprivation Using Nitrogen," WAAC Annual Meeting, Seattle, Washington, September 29-October 1, 1991.

ABSTRACT-The earliest work carried out at GCI on nontoxic control methods for museum and archive pests was that initiated by Nieves Valentin on Drosophila melanogaster and Cryptotermes brevis . This work was sufficiently promising to encourage us to pursue this line of investigation at the University of California, Riverside. This second investigation involved two related but distinct phases. In the first, mortality was determined on all life stages of twelve species in open containers. In the second, all life stages were placed in screened vials either in a wood block or at the bottom of a 0.9 liter jar packed with flour. This phase was designed to measure the time delay caused by a slower nitrogen/oxygen replacement in areas of hampered diffusion. In the first phase, 100% mortality took from 3 to 168 hours, in the second, 6 to 192 hours. Details are given of the exposure and testing protocols.

Rust, M. K., and J. M. Kennedy, "The Feasibility of Using Modified Atmospheres to Control Insect Pests in Museums," Department of Entomology, University of California, Riverside, Final Report to the (Conservation at the Getty) Institute, December 12, 1991.

ABSTRACT-This report includes the detailed Protocols for testing each life stage of the webbing clothes moth, furniture carpet beetle, firebrat, cabinet beetle, larder beetle, cigarette beetle, confused flour beetle, three species of cockroaches, powderpost beetle, and the western drywood termite to nitrogen atmospheres with <0.1% oxygen at ~55% RH. The Protocols can be used when designing nitrogen fumigation chambers.

Hanlon, G., V. Daniel, N. Ravenel, and S. Maekawa, "Dynamic System for Nitrogen Anoxia of Large Museum Objects: A Pest Eradication Case Study," II International Conference on Biodeterioration of Cultural Property, Yokohama, Japan, October 5-8, 1992.

ABSTRACT-Exposure to an oxygen atmosphere containing less than 0.1% O2 is known to cause 100% mortality of the most commonly found museum pests in a few days. This paper describes a dynamic system in which a continuous flow of nitrogen can be used to maintain a low oxygen concentration inside a sealed bag for insect anoxia with large museum objects.

Daniel, V., and F. L. Lambert, "Ageless™ Oxygen Scavenger: Practical Applications," WAAC Newsletter, 15, Nē 2, May 1993, pp. 12-14.

ABSTRACT-Ageless is the trade name of an oxygen scavenger patented and produced by the Mitsubishi Gas Chemical Company. This article illustrates the practical aspects of using Ageless, with examples and several notes of caution. Conservators interested in the experimental details and analysis can refer to our publication in Studies in Conservation. We conducted experiments to determine three important properties: (1) the effect of Ageless capacity and chamber or case volume on the oxygen concentration; (2) the effect of exposure on the reaction rate of Ageless; and (3) the effect of low relative humidity on the reaction rate of Ageless.

Lambert, F. L., V. Daniel, and F. D. Preusser, "The Rate of Absorption of Oxygen by Ageless™: The Utility of an Oxygen Scavenger in Sealed Cases," Studies in Conservation, Vol. 37, 1992, pp. 267-274.

ABSTRACT-The kinetics of the reaction of Ageless™ with oxygen were studied and an expression was obtained for the rate of oxygen reaction with Ageless: an empirical first order rate equation which involves the chamber volume and the Ageless capacity as well as the concentration of oxygen. Two factors which decrease the rate of reaction, low relative humidity, and restricted access of oxygen to the Ageless packets, were evaluated. The usefulness of an oxygen scavenger such as Ageless in prolonging the lifespan of an oxygen-free atmosphere in a museum case is discussed.

Daniel, V., S. Maekawa, F. D. Preusser, and G. Hanlon, "Nitrogen Fumigation: A Viable Alternative," Preprints, ICOM 10th Triennal Meeting, Working Group 25, Washington D. C., Vol. ii, August 1993, pp. 863-867.

ABSTRACT-The mortality of all commonly found museum pests in a nitrogen atmosphere (less than 0.1% oxygen) was evaluated at 25 ēC and 55% relative humidity. Fumigation methods which involve enclosing the object in heat sealable plastic bag, and the use of nitrogen and/or an oxygen scavenger are discussed. The feasibility of using nitrogen for fumigation in commercial fumigation bubbles as well as conventional fumigation chambers is also evaluated.

Rust, M. K., J. M. Kennedy, V. Daniel, J. R. Druzik, and F. D. Preusser, "The Feasibility of Using Modified Atmospheres to Control Insect Pests in Museums," Final Report to the (Conservation at the Getty) Institute, December 1991. Paper submitted to Studies for Conservation, January 1993.

ABSTRACT-The mortality of all life stages of pests commonly found in museums was evaluated at 55% RH and 25.5 ēC in a nitrogen atmosphere (less than 0.1% oxygen). The insects studied were Tineola bisselliella, Anthrenus flavipes, Thermobia domestica, Trogoderma inclusum, Dermestes lardarius, Lasioderma serricorne, Tribolium confusum, Periplaneta americana, Supella longipalpa, Blattella germanica, Lyctus and Incisitermes minor. The time required for 100% kill ranged from three hours for the adult firebrats to 192 hours for the eggs of the cigarette beetle.

Daniel, V., G. Hanlon, and S. Maekawa, "Eradication of Insect Pests in Museums Using Nitrogen," WAAC Newsletter, Vol. 15, Nē 3, September 1993, pp. 15-19.

ABSTRACT-The use of nitrogen gas to attain low oxygen atmospheres for eradicating insect infestation of museum objects is a feasible alternative to toxic gases. All insects commonly found in museums can be eradicated in a 0.1% oxygen atmosphere. The methods described in this paper produced and maintained the relative humidity and oxygen concentration at the required level. Results of the extended insect mortality studies at higher oxygen concentration, which are presently being conducted at the University of California at Riverside, will make this non-toxic method of insect eradication even easier for museums to use.

Maekawa, S., and K. Elert, "Large-scale Disinfestation of Museum Objects using Nitrogen Anoxia," ICOM Committee for Conservation, Preprints 11th Triennial Meeting 1996, Edinburgh.

ABSTRACT- Reusable, flexible enclosures and high-volume nitrogen supplies for large scale insect eradication treatment were investigated. The treatment system consisted of a high-volume nitrogen source, a gas humidification module, an anoxia enclosure or tent, environmental sensors, and a vacuum pump. A 10m3 volume reusable tent was fabricated from Filmpak 1193 film with an oxygen leak rate of less than 0.005% (50 ppm) per day. Thus, it could maintain the anoxic condition with no nitrogen flow for several weeks once purged to a 0.1% oxygen level. A commercially available 6m3 bubble enclosure from Rentokil has aleak rate low enough to be maintained at 0.3% oxygen by a moderate constant flow of nitrogen. Liquid nitrogen and a nitrogen generator were successfully tested as nitrogen sources for large scale anoxia systems. A humidification module was successfully redesigned for inproved accuracy and controllability of relative humidity at both low and high nitrogen flow rates. Safety issues related to large scale applications of nitrogen are discussed.

Elert, K., and S. Maekawa, "Rentokil Bubble in Nitrogen Anoxia Treatment of Museum Pests," Studies in Conservation, Vol. 42, 1997, pp. 247-252.

ABSTRACT-The Rentokil Bubble, a commercially available, portable, fumigation enclosure which was designed for use with methyl bromide (bromomethane), phosphine or carbon dioxide, was tested for its applicability for nitrogen fumigations. The unit would be a valuable alternative for museums where a costly fumigation chamber cannot be afforded or a permanent space cannot be allocated for fumigations. The performance of two bubbles, 35m3 and 6m3, was investigated for both the oxygen transmission characteristics of the materials and the gas-tightness of the enclosure. The tests confirmed the suitability of the bubble for anoxia treatment, although some practical limitations were detected, especially the size ofthe unit and possible variations in quality from unit to unit. The article describes the set-up and safety considerations of a large scale nitrogen anoxia treatment usingthe bubble.

Elert, K., and S. Maekawa, "Projekt zur Schadlingsbekampfung am GCI," Restauro, No. 4, 1997, pp. 260-266.

ABSTRACT- Abstract and article in German only.