To start with, Hulligar runs a stone website for stone repair. He has posted the same paragraphs in a hundred places on the internet. As I run across them, I set the record straight.
There have been dozens of studies on the issue of granite and radiation/Radon. Most warn of the need to test, especially those that reported granites with alarming levels of radiation, and in some cases Radon.
Currently, the Build Clean organization is testing homes in Houston, over 100 tested so far. They were funded by two quartz companies, but both submitted their product for testing. I have submitted three brands of quartz products for testing as well, but I can tell you that there is no radiation of any concequense.
Silestone also sells Sensa, a natural stone line, that has been submitted for testing as well.
One of the problems with Hulligars comments is the vast ignorance of the subject of radiation and granite. He claims that the radon will not continue after removal from the ground, which is completely false. Radon comes from the Uranium radioactive decay chain. Once the atom of Uranium has decayed in to Radium, the next step is Radon, then into the so called progeny or lower elements, which in turn continue to decay, giving off radiation as they do so.
So Radon will be emitted practically forever in our scale of time, millions, even billions of years before all the Uranium cycles through the decay chain.
Basically Hulligar is attempting to load the internet with falsehoods on this subject, whether out of ignorance or out of personal gain. I have a blog set up on these issues
I do sell solid surface along with granite, quartz, laminate and soapstone, but granite is the big seller these days. We test each and every slab prior to purchase, very easily done with a scintillator or a geiger counter.
Yesterday I sent a portion of a slab to two scientists, one that Hulligar says supports his position (he doesn't, is testing stone currently) and the other is the physcist that was on the Houston TV report. The slab in question emitted 171 times background radiation and the next slab in the bundle emitted twice that, 340 times more radiation than were present from natural sources. That last slab would give you as much radiation in an hour as you would get from a chest X ray.
So this is a serious issue, maybe 5% of granites shouldn't be sold, another 10% should carry warnings. The Chinese have been doing this for years, they test every slab and put a sticker on it. At least 15% of the high end granites sold are high enough that Chinese law won't allow it to be used in a home, day care, or hospital.