I have heard that chlorine dioxide is a poisonous, explosive gas. Isn’t it too dangerous to use in my building?
Chlorine dioxide (002) is indeed explosive at concentrations exceeding 100,000 parts per million (ppm). DRO’s fumigation process targets 25-150 ppm and our gas generation units are incapable of producing explosive levels.
The OSHA permissible exposure limit for CI02 is 0.1 ppm and DRO’s safety protocols ensure that that the gas is contained in the target area. Gas detection sensors are used to monitor concentrations outside the fumigation area and a safety zone is maintained, secure from access by building occupants. Additionally, CI02 is not toxic in the sense of a poisonous toxin. It dissipates quickly and there is no cumulative effect from incidental exposure overtime.
Why is the EPA label important?
The EPA label is your assurance that the process is completely safe and effective. The scientists at the Environmental Protection Agency, including their Indoor Environments Division, have thoroughly reviewed the science, the test data and all safety concerns. This sixteen-month review process resulted in the final label, which identifies permitted uses, procedures, safety provisions and limitations. Further, the label requires the deployment of fumigation in the field only by qualified personnel trained by DRO’s expert staff.
Does fumigation for mold abatement contradict the EPA guidelines for mold remediation?
DRO’s approved Label is fully compliant and complementary to the Guidelines. EPA’s publication, Mold Remediation in Schools and Commercial Buildings was prepared and published in 2008 by the Indoor Environments Division (IED). The IED played a significant role in the review and development of the final procedures contained in DRO’s approved label. The Label in effect amends the guidelines by slightly modifying square footage thresholds for pre-cleaning or demolition of contaminated materials and extensive cleaning of invisible mold spores on non-damaged surfaces.
The EPA guidelines suggest that duct cleaning may be necessary. Can fumigation be used instead of duct cleaning?
In some cases, yes. Recognizing that duct cleaning is often problematic using conventional methods, EPA’s Indoor Environments Division suggested the addition of HVAC equipment and ductwork treatment to the final Label. In buildings where the airflow is strictly limited to the treatment area, DRO’s standard practice is to operate air handlers in recirculate mode in order to destroy mold spores that may have settled in the ducts. Where survey data indicates severe mold contamination, usually in ducts that are lined with insulation, the label allows professional judgment in developing an appropriate treatment plan.
The American Industrial Hygiene Association has published a paper stating that fumigation is too dangerous to use in hospitals, yet you promote fumigation in healthcare facilities. Who should I believe?
DRO’s EPA Label specifically lists healthcare facilities as an approved use for chlorine dioxide fumigation.
The AIHA Position Statement, Chemical Fumigation in Healthcare Settings, was published in 2009. This document provides a brief look at the historical uses of several fumigant chemicals including hydrogen peroxide vapor, methyl bromide and super oxidized water fog, as well as chlorine dioxide. A bibliography of nineteen published research papers are cited in the evaluation. Two of these references deal with chlorine dioxide and both substantiated the effectiveness of CI02 as a fungicide. This well-intentioned position statement considered documented hazards of various chemical fumigants, but failed to include a review of DRO’s Label, approved by the EPA in 2006, as an effective application that has fully addressed each of the legitimate concerns. Further, the approved uses under the DRO Label are much narrower in scope than the applications reviewed in the position statement.
After a recent fumigation treatment, our building smelled like chlorine. Should we be concerned about breathing dangerous chlorine fumes?
Chlorine dioxide fumigation does not produce chlorine. CI02 is created by mixing chlorite (a salt) with acid in an aqueous solution. As the gas breaks down to common salts and water vapor, chlorite ions will linger for a few days, causing the chlorine-like odor. As these ions lose an electron, the odor will dissipate as well.
How long will we need to be out of the building when fumigating?
In most cases, fumigation is conducted in the evening after business hours. Chlorine dioxide generally breaks down in 6-8 hours, and the building can be re-occupied the next morning. However we suggest a day or two to air out when possible. Larger projects are often phased, require a series of fumigations conducted over a weekend, or longer.
What special procedures do you use to ensure that fumigation is safe for building occupants?
The EPA Label is very specific regarding safety protocols. In addition, a State issued fumigator license requires additional precautions. These safety protocols include evacuating facility personnel and securing the containment area; placarding and barriers; review of HVAC, fire alarms and security systems with facility personnel; removal of all plants and pets (caged animals and fish) from the area; establishment of additional perimeter safety zones; placement of gas sensors inside and outside of the treatment area; and personal protective equipment for fumigation personnel. Additionally, DRO develops and follows a site-specific fumigation plan and safety checklist for every application.
Is chlorine dioxide corrosive? Will we need to remove computers and other items from the building before fumigation takes place?
Low concentrations and short exposure times do not result in corrosion, but because some computer parts and other electronics may have soft metal components, DeepReach covers sensitive components with plastic bags or sheeting as a precaution.
How long will the beneficial effects of fumigation last?
This depends primarily on the ongoing conditions of the building being treated. Prior to treatment, the cause of the mold issues must be identified and corrected. The fumigation will attack the existing mold and essentially “re-set” the building ecology back to when the building was new. Unless there is another serious water intrusion or other event, the improved environmental condition should last indefinitely.