PHOS-CHeK W881A Class A Foam
PHOS-CHeK WD-881A is a foam-forming water additive designed for use on Class A fires; those defined by the National Fire Protection Association (NFPA) as fires in ordinary combustible materials such as wood, cloth, paper, rubber, and many plastics.
PHOS-CHeK WD-881A is a Class A Foam concentrate. It is composed of a mixture of surfactants and other performance components dissolved in a water miscible system. When the concentrate is diluted with water, it produces an excellent "wet water" which then forms a stable foam when mixed with air.
Safety Data Sheet
However, strong eye irritation and moderate skin irritation is experienced when the concentrate is allowed to get into the eye or remain in contact with the skin without washing it off. The degree of irritation, in both cases, is similar to that which would be expected from a general service, high performance liquid soap. It is recommended that skin and clothing that comes in contact with the concentrated product be washed at the earliest opportunity. All toxicity testing was conducted by independent testing laboratories using EPA protocols under the auspices of the U.S. Department of Agriculture, Forest Service.
The long term, or continual, exposure of workers to the surfactant ingredient which is present in PHOS-CHeK WD 881A concentrate and its solutions has been tested also. It was found not to pose a significant hazard to human health during its manufacture or subsequent use. It, and all other ingredients present in WD 881A, have been studied by the U.S. Food and Drug Administration and approved for use in various types of indirect food additives.
Water solutions of PHOS-CHeK WD 881A, at the recommended use concentration, will contain at least 99% by volume water. Thus, toxic impacts from its solutions will be far less than from the concentrated agent. It should be recognized, however, that such solutions will exhibit a much lower surface tension and will, consequently, penetrate through clothing, leather footwear and other potentially absorbent apparel to a greater extent than water alone. Also, as water evaporates from the solution and the concentrate strength increases, chapping and skin irritation can become greater. For this reason, it is recommended that even dilute foam solutions be removed from the skin as soon as this is convenient. Also, contaminated clothing should be washed prior to reuse.
Many, but not all, chemicals that consist primarily of carbon, hydrogen, and oxygen are degraded and ingested by naturally occurring bacteria in the soil, air and water. When this occurs, bacterial enzymes (digestive juices) break the chemical into its individual elements that can then be consumed (used for food) by the bacteria. PHOS-CHeK WD 881A contains biodegradable organic compounds that after use are converted by bacteria to carbon dioxide. Biodegradation, in effect, removes product residues from the environment eliminating potential accumulation in nature.
PHOS-CHeK WD 881A has been extensively tested and has met the recognized criteria for being classified as biodegradable in water systems. Testing has been conducted using three different types of measurements of biodegradability.
Measurement of oxygen depletion in a closed system: PHOS-CHeK WD 881A was tested by an independent laboratory under OECD Guideline 301D in which the rate of depletion of dissolved oxygen is measured as a function of time. The product successfully passed this test, showing >60% biodegradation in 28 days.
BOD testing was also conducted after only 5 days of exposure. Those tests showed that 30% biodegradation occurred during this initial period. This indicates that PHOS-CHeK WD 881A should not place a great immediate oxygen demand on the receiving waters and should, consequently, result in a reduced rate of oxygen depletion in the stream and less probability of fish kill from oxygen depletion.
Measurement of carbon dioxide evolution in an aerated system: PHOS-CHeK WD 881A was tested by an independent laboratory using OECD Guideline 301B in which the rate of generation of carbon dioxide from biodegradation is measured. The product successfully passed this test, showing >60% of the theoretical carbon dioxide evolved in 28 days.
Measurement of disappearance of dissolved organic carbon in an aerated system: PHOS-CHeK WD 881A was tested by an independent laboratory using OECD Guideline 302B in which the rate of disappearance of dissolved organic carbon (DOC) is measured. The product successfully passed this test, showing >70% removal of dissolved organic carbon in 14 days.
These data, obtained by methods emulating many of the conditions found in the real-world environment, lead the user to a degree of comfort that PHOS-CHeK WD 881A residues which enter the water environment will disappear after a reasonable period of time. This does not mean, however, that it is acceptable to flush large volumes of either PHOS-CHeK WD 881A concentrate or its water solutions into waste treatment facilities, streams or other bodies of water. Large volumes of even a biodegradable additive can shock or otherwise interfere with the operation of a waste treatment facility and disrupt the ecosystem.
We have also tested PHOS-CHeK WD 881A for its ability to biodegrade in soil. The product successfully degraded, showing 62% of the theoretical carbon dioxide evolved in 97 days. This leads to the conclusion that PHOS-CHeK WD 881A residues that remain in the soil after normal use will degrade in a reasonable time. More concentrated solutions, such as might occur from a small spill of foam concentrate, may require more time to be diluted by rainfall before they will degrade.
There have been reports of needle browning when a Class A foam formulation containing a relatively large concentration of alcohol was applied on evergreen trees. We are not aware that these reports have been confirmed, however.
Application of foam solutions on or near the edge of bodies of water should be avoided although significant impact in this case would be questionable because of the extremely low use concentrations. Moderate amounts of product run-off or foam that is flushed into streams after normal use will not likely cause a fish-kill. When amphibious aircraft scoop water from lakes and rivers, some foam solution will be expelled because of residues in the tanks and the expelling of solution from over filled tanks. Analyses of water following such an operation by the Province of Quebec (Canada) failed to find detectable quantities of the foam concentrate present the day following the operation.
When PHOS-CHeK WD 881A foam solution is applied for structure protection, it can be washed off with water. Again, water will be released from the foam and the product residues will then be biodegraded in the soil. If used within a structure, it can be picked up in the same manner as water. In this case, however, the surfaces that came in contact with the foam solution should be washed with plain water to remove any residues prior to repainting.
None of the ingredients of PHOS-CHeK WD 881A Class A foam are on the traditional federal regulatory management lists such as the SARA 313 emission reporting list or the CERCLA spill reporting list. We would encourage, however, reporting to appropriate local authorities any significant spill of foam concentrate that enters a waterway or is not cleaned up.