While impressive looking the fire departments are dumping more chemicals into california wildfires every day. The Phos-Check fire retardant is surely making the company who produces them very rich. They claim "its nothing other then a fertilizer" and on surface it looks like it:
From an australian research report:
Any amount of unaltered (un-burnt) Phos-Check would act as a direct source of N, P, S to the environment.
but just before it says:
The retardent also contains < 5% by weight of a range of performance additives that are confidential to the manufacturer, but the composition of which were made available to the consultant under a confidality agreement. The effect of high temperatures on these compounds is unknown.
Now that is a sentence that would get me worried but it goes on and does not get much more pretty.
Some of the additive compounds in Phos-Check are potentially harmful to biological systems and human health. Very little is known of the impacts of these in natural environments, including their longevity or transport in aquatic systems.
So while the main components are good fertilizers (so I still doubt dumping huge amount of sulfuric acids can be very good) the 5% that are under "confidentiality" are known to cause health problems and problems to the environments and they are know to be washed into rivers and streams with the next rain after the fires.
While I know that fires are really hell for the people living in the affected areas I also know that forest fires are a natural phenomenon that is actually helping the local area by supplying it with good natural fertilization from the charcoal burnt wood. And most of the fires ranging in the US lately can also be attributed to overcrowding areas that just do not sustain people in the long run in the manner of fashion that is common these days (level and betonize everything in sight, tear down everything in sight, put rivers into concrete walls so they can not flood anything that might need it, make the woods look "pretty" by clearing everything that isn´t in a straight line etc etc). And also people moving into these areas should surely know about the risks involved (and should look how they can help nature doing its thing to make everything more flourishing - that might include controlled fires etc).
One thing is for sure - dumping chemicals onto areas where its hard for trees to settle in the first place will make things rather worse in the long run and probably also have severe health effects on the local population.
More photos of Phos-Check dumping here.
The very scarce wikipedia entry on Phos-Check.