Recently, a new environmental phenomenon emerged here in Florida and it involves drywall that was imported from overseas during the building materials shortage of the construction boom in conjunction with the hurricane seasons of 2004 through 2007.

The drywall in question was imported from foreign sources, especially China and some of the material contains excessive amounts of sulfur and sulfur related compounds. Sources of the contaminated drywall material are highly suspected to be the mining of high sulfur content gypsum mineral from the ground. Additional suspect sources include gypsum material  (synthetic drywall) used as filter media in the smokestacks of coal-fired power plants to remove contaminants from the high sulfur content coal to prevent air pollution (flue gas desulfurization). The used and contaminated gypsum media was then reportedly re-used in the manufacturing of drywall. Recent research has show that the gypsum boards produced in China may have been processed with fecal contaminated waste water, resulting in various iron and sulfur (reducing and oxidizing) bacteria being incorporated into the drywall, that are now responsible for the sulfur chemical contamination process in the home.

Now, under certain indoor environmental conditions, the contaminants imbedded in the imported drywall, in the form of sulfur dioxide (SO_2,), hydrogen sulfide (H₂S), carbon disulfide, carbonyl sulfide, strontium sulfide and other compounds, migrate from the drywall into the indoor air. When the sulfur laden air comes in contact with the moisture located on the air conditioning coils and other metal components, an acidic solution formulates that blackens and deteriorates the coil components. The copper tubing and joint solder then fail, release the refrigerant and the coils have to be re-charged or replaced. In addition, copper wiring, copper piping and copper associated with refrigerators and water tanks inside of some homes are corroding along with reports of mirrors, jewelry and sink fixtures (i.e. faucets, valves, drains) blackening and pitting. Various electronic equipment such as computers, microwave ovens, refrigerators, stoves, dishwashers, washer/dryers, DVD players, cable boxes, circuit boards,  even light bulbs, along with any equipment that has metal components are failing too.  

It is unknown at this time what human health consequences, if any, can be attributed to the exposure of these sulfur compounds inside of the home. Reported exposure symptoms include irritated eyes and throats, coughing, sneezing, difficulty breathing, bloody noses and other symptoms similar to bronchitis and asthma.

Due to the sometimes random nature of installation and the varying degree of contaminants between boards, conditions can vary greatly from home to home. Numerous times I have seen where the lower four feet of drywall is of Chinese origin and the upper four feet is from the US (photo below) or vise versa.

If you can view the backside of your drywall by going into your attic, or get behind a wall somewhere (remove outlet covers and possibly a medicine cabinet), look for the markings “China”, "Made in China", “KNAUF Tianjin”, “Taian Taishan” , “ASTM C36" or "4feetx12feetx1/2inch  DrYwall", which are manufacturers identification markings of types of drywall known to contain the elevated concentrations of the sulfur compounds.

If you can detect a sulfur or "burnt match" - "firecracker" odor indoors, or if you have experienced problems with your air conditioning system such as coil blackening, failure and replacement, had a home constructed or drywall replaced during the time frame in question, or have concerns regarding the indoor air quality in your residence, Intuitive Environmental Solutions can assist you.

Inspection pricing starts at $225 for a residential home and includes:

·  Inspection for drywall manufacturer markings in attic spaces and inside of wall cavities,