No radon gas. There is naturally occurring methane gas. See here for discussion about methane when the elementary school was built http://www.dtsc.ca.gov/Schools/Projects/upload/Stone-Ranch-Elementary-School_Flyer.pdf
See here for what 4S was before homes were built http://www.signonsandiego.com/news/reports/4sranch/
The methane issue at 4S is no threat other than adding to the cost of construction. When my house was being built I asked the builder what all the purple colored pipes where running vertically up from beneath the foundation to vents on the roof. He explained that its a “methane remediation system mandated for all of 4S.” IF . . . . there ever where to be any amount of natural methane to percolate up through the earth to the area underneath my foundation this elaborate contraption is designed to collect the gases which MAY collect underneath the foundation and safely vent them up through the roof. The problem is that he showed me on a map where the only place the low level, but just above acceptable, amounts of natural methane were detected and its miles from where my house sits. But this is California so they then scurried around all of 4S testing and only found methane in that one place. But . . . in typical So. Cal. hysterical over reaction fashion each and every home in 4S is now mandated and outfitted with one of these “methane” gase remediation contraptions. What a huge waste of money. There NO danger, none zip, nada to anyone living in 4S from natural methane. You would have to lay on the ground and breathe the air close to the ground where the discovered the methane to even possibly be affected at all and then the net result may be smelly gas a light head for a few minutes. I guarantee you suck in 10x the amount of methane every time you drive up I-15 to Norco on the way to Las Vegas. That stinky smelly stretch is when you pass a huge cattle farm/slaughter house. All that smell??? Methane from a source . . . ahem . . . over termed “Bovine flatulence” or for those in Rio Linda “Cow farts.” See here on Norco and methane http://findarticles.com/p/articles/mi_hb5553/is_200409/ai_n22237362 Yes folks to protect you from a non-existent danger much less lethal than cow farts each home in 4S had the cost of construction raised by thousands of dollars to pay for you own custom methane remediation system in your 4S home. Its nuts.
PS. I guess the upside is I could probably hack into my sheet rock and rig up a pretty cool toxic gas contraption to also vent the air from within my house up through the same vents while all my windows and doors remained sealed. This way when the Chinese eventually take over America and try and gas everyone in So. Cal. with Nerve gas before they invade I can sit comfortably in my 4S Ranch home safe in the knowledge that my state of the art “methane remediation system” is gonna save the day.
