One of the Texas Capitol’s most distinctive features is its pink hue, courtesy of the Hill Country granite mined from Granite Mountain near Marble Falls. But behind its beauty, some have wondered whether the stone may be radioactive.
According to Lisa Bruedigan, director of the radiation control section at the Texas Department of State Health Services (DSHS), “Natural granite has the ability to release natural radiation from it, and because of the specific type, it is a little more radioactive.”
That’s because granite contains trace amounts of uranium and thorium, elements that naturally decay and emit radon gas, a colorless, odorless form of alpha radiation. “Your skin is going to block it. The clothing that you wear is going to block it,” Bruedigan told KUT News. “Where it could be an issue for an individual is when they breathe it in.”
While long-term radon exposure in confined, poorly ventilated spaces can increase lung cancer risk, Texas officials say the Capitol doesn’t face that problem. “We’ve done some minor sampling of [radon accumulation] in the past and don’t believe that it’s a problem at all,” Bruedigan said.
To find out for themselves, KUT photographer Michael Minasi and KUT producer Juan Garcia brought a Geiger counter to the Capitol. They found readings in the 30s — slightly higher than background levels around KUT’s offices but still well within safe limits. Anything below 50 counts per minute is considered normal.
A radon test kit placed in state Sen. Sarah Eckhardt’s underground office also showed no measurable accumulation.
So yes, the Texas Capitol’s pink granite is naturally radioactive, but nothing near a level of concern.
