Alternative Room Disinfection Modalities –Pros and Cons - Use of Biocidal Surfaces for Reduction of Healthcare Acquired Infections - page 193

9.3.2 Fumigation Risks: Health and Safety and Costs
While efficacy is important, so is the safety of workers and other building occupants.
Nine greenhouse workers were accidently exposed to methyl bromide in a green-
house [ 78 ]. In this incident, one of the sections of the greenhouse was being
fumigated at the same time the workers were working in an adjacent section. It was
believed that the workers were safe from exposure because their section was sepa-
rated with a glass partition wall. Unfortunately, the fumigant traveled up a sewage
pipe into the occupied section of the greenhouse. It was noted that exposure lasted for
up to 6 h and reached a concentration that peaked at 200 ppm. This concentration of
methyl bromide was 200 times the accepted exposure limit of 1 ppm [ 61 ]. All nine
workers experienced nausea, repeated vomiting, and dizziness. Some had symptoms
that included twitching of the limbs and generalized seizures, and two of the workers
were placed in intensive care for several weeks. Fortunately, the use of methyl
bromide as a fumigant has been decreasing due to its toxic effects.
Another study investigating the safety of fumigation involved methyl bromide
exposure to a family of three [ 79 ]. The accident occurred when a neighboring
house was being fumigated, and again the fumigant moved from the target structure
through sewer lines to the occupied house. This incident resulted in the death of a
newborn and severe illness to the parents. The family was exposed for an estimated
5-6 h. While actual methyl bromide level inside the home of the victims was not
measured, the concentration was estimated to be 12,850 ppm. The infant experi-
enced vomiting and severe diarrhea. The symptoms lasted 6-7 h, and upon arrival at
the hospital, the infant was declared dead. An autopsy revealed that the infant had
received severe lung tissue damage. The cause of death was due to acute pneumonia
due to aspiration from inhalation of methyl bromide. The two adults experienced
dry cough, sore throat, nausea, vomiting, dizziness and drowsiness.
In both situations, the site of fumigation was unoccupied, but in each case, the
fumigant breeched containment, exposing the workers and the family. As stated
earlier, the effect of fumigants on environmental surfaces or equipment was not
routinely evaluated in studies. The EPA found that formaldehyde did not appear to
damage surfaces; whereas, chlorine dioxide caused bleaching of surfaces, and hydro-
gen peroxide discolored dyes and had unfavorable interactions with nylon [ 60 , 80 ].
There was little evidence presented in the peer reviewed literature on the
occupational and environmental exposure that results from fumigation activities
in healthcare. On the other hand, numerous case studies and peer reviewed reports
are available on occupational and environmental exposures in non-healthcare
incidents. Some of these exposures occurred during routine operations.
9.3.3 UVC Germicidal Irradiation Risks and Benefits
As previously mentioned, the vast majority of information on UVC use as a
germicide deals with upper air disinfection. Unfortunately, there are few
laboratory-based efficacy studies on UVC for surface disinfection, and no field-
based microbiology studies of UVC as of this writing.