First and foremost, be safe. In wet environments, if the power has been restored, be particularly careful with electricity and electrical appliances. Using a plug-in GFCI (Ground Fault Circuit Interrupter) on any electrical appliance you are using is strongly recommended. Be extremely careful with heaters that use a flame source for heat; these should probably be avoided. Definitely do not use any solvent-based products until a professional has verified the functioning of the heater.
Floodwater may have been contaminated with sewage, in which case due precautions should be taken to avoid exposure to pathogens such as bacteria and viruses. Wear appropriate gloves; surgical (latex or nitrile) or even kitchen gloves. The water may also be contaminated with oily material that floated on the surface or other hazardous or toxic material that was washed along with or dissolved in the water.
Mold grows in still, humid environments. Do not wrap wet or even freshly dried paintings in plastic; you are all but guaranteeing mold growth. Paintings exposed to salt water may develop mold growth more slowly, but it will still grow.
Mold digests the substrate upon which it grows. It also forms stains that are very difficult and sometimes impossible to remove. Mold is also a potent allergen, and people can become highly sensitized. Sometimes this can happen suddenly after repeated exposure with no or only mild symptoms. Mold can also create mycotoxins, poisons that are hazardous to everyone. While fairly rare, this is a real risk.
So, to prevent mold, keep air circulating and keep things as dry as possible. Remove wet insignificant materials—wet carpets, etc.—from your workspace, as these will just add moisture to the air. Dehumidifiers, if available, will remove water vapor from the air and lower the relative humidity. Heaters lower the relative humidity but don’t remove the moisture from the air; warm air just holds more water. In any event, do not overheat or excessively dehumidify the air.
When dealing with mold or working in a moldy environment, proper protective equipment is necessary. Wear gloves, as suggested above. Also wear, at a minimum, a P95 or N95 dust mask (properly a Filtering Face Piece, or FFP)—an N99 or N100 would be better. Technically, you should be fit-tested to make sure the FFP is fitting your face properly and filtering the air you inhale. Short of that, if you feel warm air slipping between your face and the mask when you exhale, you are not getting anything near a good fit. Try readjusting the mask, and if that doesn’t work try a different brand, as each brand fits individual faces slightly differently.
A half-mask respirator with N100 cartridges or combination cartridges will be much more effective and is easier to fit test. However, a half-mask or full-face respirator requires extra work to pull air through the filters. You should not wear this type of respirator if you have respiratory health or cardiac issues unless your physician has cleared you. OSHA has an evaluation form for a health professional to assess your fitness to wear a respirator. Again, if you can’t get or haven’t had a formal fit test, there are inhalation and exhalation tests that you can perform to get some sense of the fit. These steps can be found online.
Ideally, you will be wearing a Tyvek suit in a mold-contaminated environment, possibly with a hood and foot covers. If you are not wearing a suit or coverall over your street clothes, be sure to change clothes, including your shoes, when leaving the moldy space. If possible, wear something on your head as well. You don’t want to bring the mold home with you.
Eye protection is also recommended, as you don’t want to get an infection in your eye. Also the eyes drain into the nose, so allergens can be washed down into your body with tears.
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