# Art/Object Issues > Conservation >  Vikane gas in the treatment of potentially infested collections materials

## T. Ashley McGrew

Below is a response to a question on the Registrars Committee listserve about the use of Vikane on collection material.


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Hi Amanda,

Here are a few thoughts on your topic. 
Vikane (trademark term for sulfuryl fluoride) and methyl bromide are the two fumigants that have been used to treat pests in museum collections recently. Of the two I believe that Vikane is the preferred fumigant (I believe that methyl bromide can react with compounds containing sulfur - sulfuryl fluoride doesn't really seem to react with basically anything). 
Luckily it is also the one that I am personally familiar with. 
During the collections move of the Smithsonian Institutions - National Museum of the American Indian we used three treatments to eliminate potential infestation of collections materials - Low Temperature (Mary Lou Florian will haunt your dreams if you call it freezing [not a high enough moisture content to actually freeze]), CO2, and Vikane. The three are listed in the order of the volume of objects that were treated with each. 
It is true that the trend is away from chemical treatments but choices need to be made based on practicality and the truth is each method has its own best use. 
Vikane in particular is used in cases where the objects were too large to easily fit into a freezer or "bubble".
It also has the advantage of being much faster than either Low Temp or CO2 (or Nitrogen anoxia as far as that goes). 
The most up to date information that I have is that it leaves no residue on collections material. 
I would mention that I also know that it is currently in use by at least one other Smithsonian museum. It's advantages include speed and the fact that it has a high rate of penetration making it effective for even very thick organic objects. Also there are not the potential complications related to humidity change that can go along with the use of CO2 - which is also happens to be pretty hazardous to human folk as well as insects. 

One of limitations in the use of Vikane to consider is the need to remain within a specified temperature range for it to be effective, so if you are fumigating outside or in a trailer you might have seasonal issues. 
Probably of more importance though is that it is a restricted chemical that may have prohibitively complex restrictions in many urban areas. I have heard of museums sending collections materials in tractor trailers to be treated in other areas that permit its use. Luckily in many parts of the country, this is really not an issue. In some areas though you may have to provide 24 hour supervision of the area where the gas is in use to prevent accidental exposure to individuals who could be there without authorization. 

Having dealt with these methods myself in the past, I would recommend that anyone weighing the use of these options consult directly with conservators who deal with these issues on a regular basis. You might want to start with contacting the OSG (Objects Specialty Group) at AIC. 

I mention this because I have read descriptions of the use of preventive IPM treatments (low temp in particular) on listserves that were totally inaccurate. Presumably the comments were based on what someone was taught "back in the day", but in many cases I feel confident in saying that the what they describe was not accurate even when they were originally instructed.
If you have any specific questions that I could help with or if you have trouble contacting a conservator, don't hesitate to communicate directly and I can provide a contact or two.
Best regards,

Ashley

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## T. Ashley McGrew

A reply to an idividuals concern that "sulphur" might be added to Vikane as a safety precaution and that it might result in damage to some collections materials.

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Hi Gale,

I am not sure about your particular situation (vendor etc...) but it seems that the most common commercial additive (for fumigation of houses and such) on the West coast at least is Chloropicrim which basically irritates the eyes, and mucous membranes - kind of like a tear gas. It is described as a "warning agent" and its purpose is to keep from killing hapless burglers and curious children that might sneak into a tented house. The EPA has a page that discusses this - 

http://www.fluoridealert.org/pesticides/sulfuryl.f.vikane.epa.htm

I didn't think that the "Vikane" that we used a few years ago contained any additives. I spoke with some one at Lloyd Pest Control and in San Diego who confirmed that normally they use the additive in tented homes but when they use the portable fumigation chamber that they haul onsite (say to the one of the Balboa Park complex museums) they do not use the additives (partly because it can be maintained as a secure environment). 
The use of additives seems to vary from company to company, situation to situation, and from one municipality to another so it is worthwhile to ask around.


Also if you are not familiar with it already a great resource for all things "buggy" in the museum environment is - 

www.museumpests.net

they have good information on a range of IPM related topics but the specific link that discusses fumigation is 

http://www.museumpests.net/treatment.asp?defaulttab=1

The folks involved in this organization are all top notch.
Have a great weekend!

Ashley

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## sfhdweb

Thanks for sharing great information.

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## T. Ashley McGrew

You are welcome. 
As often happens when someone posts to an older thread I look back at it and go "What was I thinking?" 
In this case I noticed that I had not included a link to a JAIC article on the topic.

http://cool.conservation-us.org/cool...29-01-005.html

I would add one comment about the article. Like any good article it covers the topic thoroughly, but on reading it again before posting the link I must say that it makes the process sound much more complex than it really is. I have been involved with the use of Vikane four different times and it was a pretty straight forward process. The caution that is probably most applicable to museum use is to make sure that the vikane doesn't blow straight on to an object directly out of the dispersal hose (in liquid form). That is not hard to do since the liquid form of vikane rapidly volitizes and especially in the kind of small applications commonly found in a museum setting the use of a heat exchanger, or even fans to circulate fumes is often not required. Similarly the use of a measuring device like a "Fumescope" isn't a requisite item. Remember also as you read the article that for any of the details mentioned that do apply to your project the best source of information will be the licenced fumigator required by law to perform the task. To him or her this will be a relatively small, simple, but interesting project (most are used to fumigating multi-story houses) and I am pretty sure they will be happy to address all of your concerns. As in all situations that require the use of outside professionals - if they don't answer your questions to your satisfaction - hire someone that does.

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## aaagul45

I spoke with some one at Lloyd Pest Control and in San Diego who confirmed that normally they use the additive in tented homes but when they use the portable fumigation chamber that they haul onsite (say to the one of the Balboa Park complex museums) they do not use the additives (partly because it can be maintained as a secure environment). ???

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## T. Ashley McGrew

The most well known use for Vikane is to exterminate household pest infestation. The whole house is "tented" usually with bright colors to draw your attention. But what may act as a warning for adults can appear to be giant bouncy house to inquisitive kids. The additive is designed to make it uncomfortable to be in the enclosed space and act as a warning if there are leaks things like that. Since we are treating valuable artifacts we are used to providing a secure environment regardless of the kind of treatment being performed.

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## ghostwriter

Sulfuryl fluoride is highly toxic to all post-embryonic life stages of insects (UNEP 1994), eggs of most species are less susceptible (DowElanco 1996a; Bond 1984). The efficacy of sulfuryl fluoride depends on the concentration reaching the target pest and the duration of exposure. As a result, the dosage of sulfuryl fluoride required for a specific pest is calculated in "ounce-hours," ounces of Vikane multiplied by hours of exposure. In general, insect eggs require a higher ounce-hour dosage of sulfuryl fluoride compared to later life stages (i.e., a 10-fold increase in dosage for some insect species) (UNEP 1992, UNEP 1994). However, the ability to control egg stages of social insects (i.e., termites and ants) is not necessary because these newly hatched larvae cannot survive without adult care. Furthermore, the higher dosages required to control insect eggs can be obtained by increasing the exposure time, concentration of sulfuryl fluoride, or a combination of the two. Fumigators use a "fumiguide calculation system" to determine the amount of Vikane required for specific pest and fumigation conditions (DowElanco 1994 and 1996a).
Sulfuryl fluoride prevents insects from metabolizing the stored fats they need to maintain a sufficient source of energy for survival by disrupting the glycolysis cycle (Meikle et al. 1963). Mortality may be delayed for insects for several days following fumigation (Osbrink et al. 1987), therefore insects that have received a lethal exposure to sulfuryl fluoride may still be alive immediately following fumigation (no longer than 3 to 5 days for termites) (DowElanco 1994). Sulfuryl fluoride has also been demonstrated to reduce oxygen uptake in insect eggs (Outram 1970).

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