Discovery
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Discovery
From Bad, to Worse
Why Should I Be worried?
Can Mold Cause Cancer?
Summary
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Appendices
Just to make it clear that raw sewage is not the kind of thing you want laying around, here is some background. The sewer was unclogged 40 feet from the access pipe (which was in the front yard). The sewage backing up into my apartment was from the main sewer, well beyond the toilet trap. According to the Institute of Inspection, Cleaning, and Restoration Certification (IICRC), which is one of the leading authorities on flood cleanup:
"Toilet backflows that originate from beyond the trap are considered black water, regardless of content or color...If you're not convinced that raw sewage is bad, look at this table.
Category 3 [Black Water]: Grossly unsanitary water containing pathogenic agents arising from sewage or other contaminated water sources and having the likelihood of discomfort or sickness if consumed by or exposed to humans...Also referred to as 'Black Water'...
If flooding is primarily from the outside sewage system, occupants should be moved out and restoration should begin immediately"
Upon reaching the apartment, the first thing that Wall to Wall Carpet did was to remove as much of the raw sewage as possible. So far, this agrees with all of the health recommendations and guidelines (in any other state, they would be regulations). All of the documents agree that the first priority should be removing all standing water (or sewage) and all organic material as quickly as possible.
One part of this initial cleanup that was noticeably absent was the removal of contaminated material. The closet under the stairs was full of broken-down cardboard boxes. Cardboard is a very absorbent material, and would have sucked up the sewage like a sponge. Here is a quote from "Remediation of Sewer Backflows":
"This penetration [of wood and gypsum paper] with water and disease causing (or opportunistic) microorganisms, may pose a serious health risk to occupants of the building. Organic materials and water saturated materials can be used as a substrate for growth of microorganisms (such as gram-negative bacteria and toxogenic fungi)"By the time I cleaned up the closet, the cardboard boxes were a soggy mass. After reading about it, I shudder to think about what might have been growing in the mass of soaked cardboard.
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In this photo, you can see the results (Make sure to click for the full size photo). This is what the airbox looked like when I unscrewed the vent and looked inside in July, 2000. There are two things that I would like to point out. First, you will notice the 2" high stain in the drywall along the side of the airbox. Second, if you look closely at the 2x4 at the back of the airbox, you will see that it is visibly stained dark. On top of the 2x4 is a very distasteful looking film.
Just what would happen to 2" of raw sewage left in the air ducts to dry? Here is a description from "Cleaning Up Your House After a Flood":
"If left for more than a few hours, standing flood water [not to mention sewage] can be rich enough in nutrients and inoculated with enough bacteria, molds, amoeba, and other contaminants to grow a rich broth of organic materials."Not exactly the kind of thing you want in your air ducts.
After Wall to Wall Carpet finished cleaning up (most) of the standing sewage, they started on the carpet. They first vacuumed up all of the sewage that they could get, shampooed the carpet, then vacuumed again. To dry the carpet, they placed a large blower in the closet with the outlet tucked under the edge of the carpet. The airflow lifted the carpet 18" - 24" off of the floor. During this time, Wall to Wall told me to run the A/C to remove the humidity. The carpet took several days to dry.
If, for example, my water heater had ruptured, I would feel perfectly comfortable using this method to remove the tap water and dry my carpet as quickly as possible. However, I am not so sure that I want a large fan blowing "pathogenic agents" and "toxogenic fungi" from raw sewage into the air I'm breathing for several days. With the A/C running, anything coming off the carpet would have been spread throughout the apartment.
Here is what the IICRC has to say on the subject:
"Remove and dispose of carpet that has been saturated with category 3 water...In fact, none of the numerous documents given to me by the health department recommended trying to save a carpet contaminated with sewage. Most of the documents were very explicit about removing the carpet immediately, since it is almost impossible to get clean. Why is the carpet such a problem?
Remove and dispose of carpet padding that has been contaminated by category 2,3 water, without exception."
In my apartment, the humidity was always high during the muggy NC summers. This was partly due to the design of the building, partly due to the heat pump (heat pumps tend to be less effective dehumidifiers) and partly due to the way the A/C was operated (see humidity section). As a result, the humidity in the apartment was usually between 60% and 75%. At 76 degrees and 70% humidity, the dewpoint is around 65 degrees. Concrete slab foundations (like the one my carpet sat on) are typically around 60-65 degrees. At 65 degrees or lower water would start to condense on the slab. For the sake of argument, let's assume that the bottom of the carpet was slightly warmer, say 70 degrees. At 70 degrees with a dewpoint of 65 the humidity is 85%.
Now, lets review. A carpet (nutrient source) contaminated with raw sewage (supplies all sorts of bacteria and mold spores) at 70 degrees and 85% humidity (near optimum conditions for mold growth). The health department did not think that this is a good idea. I personally will never look at a carpet the same way again.
The question of whether or not conditions were favorable for mold growth would
seem to be answered by this picture (be sure to click for larger
image). The photo shows the underside of a bookshelf that was sitting on the
carpet. As you can see, the underside of the bookshelf is covered with a rather
unappetizing greenish-purple mold.
After Wall to Wall Carpet finished shampooing the carpet, they took a spray bottle and sprayed the surface of the carpet. Wall to Wall Carpet explained that this would prevent mold from growing. According to "Cleaning Up Your House After a Flood":
"It is unlikely that any chemicals are both safe to humans and generally effective at preventing the growth of these microorganisms[mold]."According to IICRC:
"Biocides must be applied by properly protected persons and only in unoccupied buildings"The spray probably was effective at one thing, according to the health department:
Preventing mold from growing on the surface of the carpet, where it was visible.