The entire LA and San Francisco Bay Area regions were for half a century dumping grounds for far worse stuff than most of the radiological hazards at Santa Susana Field. The worst hazards at Santa Susana Field itself were probably the rocket-related research and associated non-radiological chemicals. This seems confirmed by the Woolsey fire, when nobody was able to detect radioactive contamination.
Detection of radionuclides is easy and reliable; detection of all the myriad other industrial chemicals less so. California hosted a disproportionate share of defense and industrial research and production facilities which are known to have released insane amounts of non-radiological hazardous waste, often adjacent to large populations. As cities expanded many communities, rich and poor, now live atop of it. Even just run-of-the-mill lead hazards are pretty bad in California because the state rapidly expanded coincident with peak usage of lead in fuel and paint.
Unless you live on a property far outside coastal LA and Bay Area cities, it's not entirely unreasonable to reflexively pave over backyards, etc, especially if you have kids. Alternatively, pay a sizable amount of money for soil testing.
Testing soil samples for lead is cheap/free, though, through some government programs; just be prepared to resort to plan A. When we bought our house in the Outer Richmond of San Francisco, I meticulously took samples of our backyard and shipped them off for spectroscopic measurements through one of those programs. Unsurprisingly they all came back near or above the threshold for "absolutely don't garden here". A couple came back near the threshold for "you're required by law to inform the EPA", which was pretty insane because the thresholds for mandatory declaration of soil lead contamination are (at least in non-commercial contexts) way, way, way above recommended safe limits; this is to minimize the economic burden of remediation.
A family member of mine develops small and medium size apartment complexes in Southern California and she deliberately avoids soil tests. She assumes any parcel of land in a populated area is contaminated and designs projects accordingly--e.g. cover any common areas where kids might play with known clean soil from elsewhere. She also reminds contractors to follow basic safety measures, like not washing their work clothes in the same wash load as other family members. If she voluntarily tested as a matter of course she'd subject herself to expensive, mandatory remediations, and construction of anything except luxury housing wouldn't be economically viable.
Comments
The entire LA and San Francisco Bay Area regions were for half a century dumping grounds for far worse stuff than most of the radiological hazards at Santa Susana Field. The worst hazards at Santa Susana Field itself were probably the rocket-related research and associated non-radiological chemicals. This seems confirmed by the Woolsey fire, when nobody was able to detect radioactive contamination.
Detection of radionuclides is easy and reliable; detection of all the myriad other industrial chemicals less so. California hosted a disproportionate share of defense and industrial research and production facilities which are known to have released insane amounts of non-radiological hazardous waste, often adjacent to large populations. As cities expanded many communities, rich and poor, now live atop of it. Even just run-of-the-mill lead hazards are pretty bad in California because the state rapidly expanded coincident with peak usage of lead in fuel and paint.
Unless you live on a property far outside coastal LA and Bay Area cities, it's not entirely unreasonable to reflexively pave over backyards, etc, especially if you have kids. Alternatively, pay a sizable amount of money for soil testing.
Testing soil samples for lead is cheap/free, though, through some government programs; just be prepared to resort to plan A. When we bought our house in the Outer Richmond of San Francisco, I meticulously took samples of our backyard and shipped them off for spectroscopic measurements through one of those programs. Unsurprisingly they all came back near or above the threshold for "absolutely don't garden here". A couple came back near the threshold for "you're required by law to inform the EPA", which was pretty insane because the thresholds for mandatory declaration of soil lead contamination are (at least in non-commercial contexts) way, way, way above recommended safe limits; this is to minimize the economic burden of remediation.
A family member of mine develops small and medium size apartment complexes in Southern California and she deliberately avoids soil tests. She assumes any parcel of land in a populated area is contaminated and designs projects accordingly--e.g. cover any common areas where kids might play with known clean soil from elsewhere. She also reminds contractors to follow basic safety measures, like not washing their work clothes in the same wash load as other family members. If she voluntarily tested as a matter of course she'd subject herself to expensive, mandatory remediations, and construction of anything except luxury housing wouldn't be economically viable.