By Stefanie Bauvois, Romy Ruigrok and Sanne Wynants

The presence of asbestos in museum collections has become more evident in recent years. Due to its useful properties (resistance against fluctuating temperatures, moisture repellence, electrical insulation, etc.), asbestos is not only found in building elements but is also found in everyday objects as well. Detection and safeguarding to minimize health risks can be challenging for museum workers without the proper training and understanding of how best to respond to asbestos in their collections. Options are often limited to either careful storage and management or removal of the contaminating object.

Inspired by a growing awareness around this issue, and our endeavour to better assist institutions with handling contaminations, we conducted the following study on how to best respond to outbreaks of asbestos by means of consolidation and preventive care. We anticipated a twofold outcome: 1) consolidating contaminated components and 2) designing a protective packaging method which meets handling and storage requirements for the object in addition to blocking asbestos fibre emission.

On consolidating asbestos

The aim of our initial experiment was to maintain the integrity of the object as well as to minimize potential risks for museum workers and visitors. The tests were deemed successful when objects could be handled without fibre emission exceeding legal thresholds. Our team of conservators from varying specialisations selected eight well-known consolidation mediums for experimentation with the intention of establishing application methods that could be conducted by museum workers without professional conservation knowledge or training.

To maintain safety and protect the team, the consolidating agents were first studied by applying them to materials bearing a strong likeness to asbestos: textile, cardboard and sheet material. These preliminary tests allowed us to eliminate consolidation materials and methods that didn’t comply with the specific needs of the material. Agents that risked altering the appearance of the material or endangering the integrity of the object were thus eliminated early on in the process. The final set-up consisted of eight consolidation mediums applied either by brush or airbrush.

Samples were tested on parameters corresponding to changes in appearance before and after application.

Changes to the following components were therefore recorded: gloss (Gloss Meter PCE-GM 60 plus), colour (WR10 High-precision Digital Colorimeter Colour Difference Energy Meter Tester), texture, weight and size. The tests were repeated after exposing the samples to extreme environmental conditions including elevated humidity and temperature as well as accelerated UV-aging (BGD 852 Bench UV-light Accelerated Aging Chamber). Furthermore, we tested the ability of the consolidation mediums to adhere fibres to the surface of the material. We measured this by applying adhesive tape—commonly used to test fibre emission in asbestos—to the samples and by studying the results via optical microscopy. Additionally, the consolidating agent needs to be able to penetrate the surface sufficiently enough to attach the asbestos fibres to the material. The consolidation mediums were mixed with eosin (a red fluorescent dye) before application, and after their application, cross-sections were taken and analysed with optical microscopy to assess the penetration of each medium, via the dye marker, into the material samples.

Our main goal was to derive a consolidation method that could not only be implemented by museum workers onsite, but would also meet feasibility and time constraints without causing undue harm to the contaminated objects. In the end, two products met the aforementioned standards: Klucel G and Methocel 4AC. With the preliminary testing and medium selection completed, we selected the following collection items for additional testing: 1) a small flatiron with cardboard asbestos, 2) a pot holder made with cardboard asbestos and 3) a curtain from a movie projector made with textile asbestos. Prior to consolidation we tested these objects for their compatibility with the chosen consolidants.

Klucel G was applied in three layers by brush to the cardboard components, and Methocel 4AC was likewise applied to the textile. A fibre count test was conducted on the immediate and surrounding area around the test site before and after application of the medium; these consolidants were sufficient in adhering fibres to the objects’ surfaces, minimizing health and safety risks when on display, in storage and even when handled. However, some fibres were detected on samples taken from a damaged area of the curtain; this finding suggests that although this method is sufficient in consolidating objects in good condition, further research is needed to establish how best to treat objects in poor condition. Furthermore, even after consolidation, fibre emission can still occur when an object is damaged, so we recommend caution at all times.

On designing protective packaging

Consolidating asbestos risks altering the appearance of an object, whereas taking preventive steps to package the affected item does not pose a threat to its aesthetic integrity. However, industrial guidelines for the remediation of asbestos encourages the use of plastic bags with a thickness of 200 μm, which could encourage processes of degradation. Working from a case-study (an incubator containing cardboard asbestos), we researched several possible packaging methods and materials before developing a design and building a prototype.

The prototype was made using Tyvek 1442R. This fabric is well known in the field of cultural heritage preservation as it provides a breathable, yet closed, environment for the object. This type of Tyvek is commonly used to produce HAZMAT suits when working with risks such as dust, mould and asbestos. The fabric was draped around an internal structure of aluminium tubes to create adequate space between the object and the fabric. The tubes were pinned onto a medium-density fibreboard which was coated so that no volatile compounds from the board would interfere with the object housed inside the enclosure. In order to assess the possible fibre emission through the Tyvek, a smoke test was conducted inside the packaging. Results showed no strong emissions except through the zippers we installed to provide access to the object. In conclusion, the prototype showed promising results in containing the fibres, but additional research needs to be done to further develop a safe and sustainable packaging method.

This article highlights some of our initial insights into the possibilities around taking preventive and consolidation measures to safeguard asbestos in museum collections. Certainly, more research can (and will) take place to ultimately develop a safe method for displaying, storing and handling asbestos contaminated objects. A cautious approach is needed when dealing with such objects, but hopefully these results will provide reliable short-term solutions to minimizing fibre emission and the associated risks to visitors and museum workers. We hope that this article encourages the NiC community to also consider how best to tackle the problem of asbestos in collections, and we welcome any further suggestions that you might have on the subject. Our explorations have only just begun.

To contact the authors or learn more about the project, contact them here: info.belgie@artsalvage.eu

Author bios:

Stefanie Bauvois holds a master’s degree in conservation and restoration (2013) and cultural management (2014) from the University of Antwerp. She is currently working at Art Salvage (Belgium) specialising in ceramics and related materials as well as in preventive care for collections. Stefanie is also head of the ceramics conservation department at the University of Antwerp and is part of the ARCHES research group.

Romy Ruigrok has a bachelor’s degree in conservation and restoration (2017, Antwerp University) and a master’s degree in museum studies (2020, Leiden University). She is currently working at Art Salvage/Art Conservation NL as a paper conservator and preventive conservation consultant. Additionally, she is studying to become a bookbinder.

Sanne Wynants graduated with a master’s degree in conservation and restoration (2014), specializing in 3D objects, stone and stone-related materials. Starting her career as a restorer at Art Conservation (Netherlands), she is currently managing director of Art Salvage (Belgium) overseeing day-to-day tasks as well as specializing in preventive care for heritage collections.

(Read the article in the February-March 2022 "News in Conservation" Issue 88, p. 24-28)