Mold & Pest

The four phases of CO2 anoxic oxygen deprivation and dehydration treatment are as follows:

  • Phase One Testing for leaks with the TIF Instruments 8800 Combustible Gas Detector. Generic canned air was sprayed in the interior corners and seams to test the seals. The combustible gas meter can detect the propellant.
  • Phase Two Purging and flushing the enclosed environment of ambient air to reach a low oxygen 0.1 – 0.01% concentration.
  • Phase Three Continued flushing with direct drawn suction and CO2 induction filling, to contract and expand the volume of interior space, until 85% CO2 saturation mixture is achieved. Once this point has been reached it must be kept constant 24/7 for a period of 21-25 days for pests, or 5-7 weeks for microbial infestations.
  • Phase Four Evacuation of CO2 by vacuum pump to the outside exterior of the building and repeated flushing with fresh ambient air, until the interior CO2 monitor reading is below 500 PPM. Then the tent encapsulation can be opened and the objects removed to Clean Stage Isolation Room 1.
Microbial/Fungal Species Identification

Our Conservation Studios specialize in Mold and Pest Abatement treating various types of infestations in art collections, furnishings and objects. Our Assessments, on-site test sampling, and protocols review the initial mold testing data and then perform in-situ follow-up tests to identify the microbial species and create a treatment plan.

The initial on-site condition assessment select sample testing results using tape lifting and air samples, and ATP Rapid Hygiene Bioluminescence and agar swab culturing can show and identified the following types of concomitant mold species seen growing with underlying mycelial and/or sporulating structures: Acremonium, Alterneria, Aspergillus-Penicillum, Basidiodpores, Chaetomium, Cladosporium, and Stachybotrys. Molds, fungi, bioaerosols, bacteria, mycotoxins, volatile organic compounds (VOC’s), and microbial microorganisms are all common to both indoor and outdoor environments. Mold growth can suddenly appear and rapidly advance its spread within 24 to 72 hours. Understanding which ones pose a threat to potentially damage and spread contamination amongst objects, collections, our controlled environments and their stewards is an important initial step.

Cellulosic and proteinaceous species survive by producing their own digestive enzymes to break down cellulose materials into soluble sugars, then often producing a waste that provides a secondary food sustenance for a concomitant pest infestation or bacterial infection. In some cases the fruiting bodies and flora of the fungi spores and hyphae alone can be the food source for mites. The danger here is that pests are mobile and can be on the move within collections, transporting and spreading contaminant spores, microbes and other cohabitant bacteria wherever they travel.

Mold spores germinate from hyphae and a network of branching mycelium that is not visible without magnification. When fungi and microorganism are in a blooming cycle the mycelium branches are spreading out their network of roots through the supporting (host objects’s) substrate below the surface. Then the hyphae sprout as long tethers, sometimes as fine tangled filaments in a fuzzy mesh, these can develop in nearly any color depending on the species. From these branches develop the large bulbous fruiting flora that are the spores that will burst into the atmosphere to become airborne. Once aloft, these spores will carry much like a tiny umbrella in the wind, and wherever they land a new colony is settled. These spores can remain dormant rather indefinitely, left undisturbed, and suddenly reactivate into a new branching mycelium colony given the opportunity of a hospitable environment.

Hygroscopic materials, most especially dust and other particulate matter are optimal host substrates for mold growth as they can attract and retain water molecules with an electrostatic charge, thereby sustaining a moisture content and increasing the RH%.

Any objects tested positive for active microbial growth, with prolific mycelium branching CFU’s and background blue-green plant flora fungi or further evidence of black powder molds must be thoroughly remediated to prevent further spreading and colonizing to other objects within the collections—whether in storage or on display.

Beware the use of Biocides, Bleach,
Fumigants, Fungistats and Fungicides

The application of compound chemical solutions with supposed anti-fungal/anti-microbial agents can resolutely be counterintuitive. Much in the same way the scientific evidence has long pointed the finger at systemic overuse of antibiotics and anti-bacterial agents as the direct correlation to the proliferation of increasingly resistant and mutating strain of bacteria. Similar observations have been recorded in microbiology. Many species of mold have become totally resilient to industrial fungicides and anti-microbial agents. I often warn clients not to use mildew stain removers or bleach as they can actually incite mold growth, and explain why with this analogy. If you apply a mildew stain remover or bleach (NaC10) sodium hypochloride to your shower tiles, only the blooming surface flora is being attacked. The shower will appear clean and the black-brown discoloration has been removed. However, the microorganism, the branching mycelium that is not visible to the naked eye, hidden in the tile grout, is alive. The base microorganism reacts to this injury, having been harmed, is shocked and puts all its energy into an accelerated reproduction phase building up its next blooming cycle. Thus within two to three weeks the shower once again has black-brown mildew growing, and the cycle is endless, due also in part to the hospitable moist environment.

Chemicals that claim to kill or stop mold are still widely used and marketed today. The museum, conservation and archive fields have for the past decade or so, veered away from these toxic and invasive treatment approaches, as the ongoing and longterm residual effect can be both detrimental to the objects and harmful to the collection stewards. Dimethyl Benzyl Ammonium Chloride (Alkyl C12-16)  CH3(CH2)17N (CH3)2CH2C6H5CI a common quaternary ammonium compound, is a group of ammonium salts in which organic radicals have been substituted for all four hydrogens of the original ammonium cation. They have a central nitrogen atom which is joined to four organic radicals and one acid radical. The organic radicals may be alkyl, aryl, or aralkyl, and the nitrogen can be part of a ring system. They are prepared by treatment of an amine with an alkylating agent. They show a variety of physical, chemical, and biological properties and most compounds are soluble in water and strong electrolytes. Such compounds can include: Benzalkonium, Chloride, Benzethonium Chloride, Cetalkonium, Chloride, Cetrimide Cetrimonium Bromide, Cetylpyridinium Chloride and Stearalkonium Chloride. They have properties of disrupting micro-organisms’ cell processes and surfactants. These compounds, as well as Thymol (C10H14O), methyl bromide, borate and ethylene oxide are used as the dominant active ingredient for many commercially available products, including antimicrobials, detergents, sanitizers, phase transfer catalysts, disinfectants, slimicidal agents, algaecides and emulsifiers. None of these compound chemical agents should be considered acceptable ingredients in any conservation formulary treatment solution and application for mold remediation and abatement.

CO2 Dry Ice Micro-Dusting

This treatment approach is not ideal for all medium and materials, as some weak objects cannot withstand the initial force, similar to that of the volume air pushed from a hairdryer. CO2 dry ice dusting could be successfully used to surface clean outdoor sculpture, medium and large furniture, chairs, frames, trunks, pedestals and books.

Surface cleaning with frigid, below freezing dry ice ‘blasting-pellets’ has been utilized in industrial manufacturing for sometime, and in recent years the softer less invasive using very small granules in place of the rice grain size pellets, has begun to be adopted into the field of conservation science. The application of this treatment is relatively inexpensive, simple to perform, control and minimal equipment is required. A mixture of compressed air, CO2 and CO2 ice particles are directed through a hose attachment and wand with an adjustable nozzle to control the area of space that will be diffused.

The dusting particulate is propelled towards the surface at an extremely high speed, with an initial temperature of -78.5c. As the CO2 dry ice explodes across the debris field and soiled surface. A thermal shock reaction takes place causing any unwanted materials to shrink, expand, become brittle, loosen and quite literally fall away.

This instant temperature change sublimates the ice particulate crystal into gas before it reaches the underlying object substrate, transferring minimal kinetic energy upon impact. The gas has 800 times greater volume and spreads out underneath the surface material speeding up the removal. This rapid transformation from a solid to gas form also causes microscopic shock waves, which like sonic shock waves, assist in removing the contaminant from the surface. This process allows for a safe, gentle, non abrasive alternative to aqueous surface cleaning that is environmentally neutral.

Contact us with any questions you may have regarding infestation or microbial attack of your fine artworks and collections.