Is Your Granite Countertop
Dangerous To Your Health?
As the popularity of granite countertops has grown in the last
decade demand for them has increased tenfold, but most
aren't aware that some types of granite contain high levels
of uranium, which is not only radioactive but releases radon
gas as it decays.
According to the Marble Institute of America, a trade group
representing granite fabricators so have the types of
granite available. For example, one source, Graniteland (graniteland.com)
offers more than 900 kinds of granite from 63 countries. And
with increased sales volume and variety, there have been more
reports of “hot” or potentially hazardous countertops,
particularly among the more exotic and striated varieties from
Brazil and Namibia.
“It’s not that all granite is dangerous,”
said Stanley Liebert, the quality assurance director at CMT
Laboratories in Clifton Park, N.Y., who took radiation measurements
at Dr. Sugarman’s house. “But I’ve seen a
few that might heat up your Cheerios a little.”
Allegations that granite countertops may emit dangerous levels
of radon and radiation have been raised periodically over the
past decade, mostly by makers and distributors of competing
countertop materials. The Marble Institute of America has said
such claims are “ludicrous” because although granite
is known to contain uranium and other radioactive materials
like thorium and potassium, the amounts in countertops are not
enough to pose a health threat.
Indeed, health physicists and radiation experts agree that
most granite countertops emit radiation and radon at extremely
low levels. They say these emissions are insignificant compared
with so-called background radiation that is constantly raining
down from outer space or seeping up from the earth’s crust,
not to mention emanating from manmade sources like X-rays, luminous
watches and smoke detectors.
But with increasing regularity in recent months, the Environmental
Protection Agency has been receiving calls from radon inspectors
as well as from concerned homeowners about granite countertops
with radiation measurements several times above background levels.
“We’ve been hearing from people all over the country
concerned about high readings,” said Lou Witt, a program
analyst with the agency’s Indoor Environments Division.
Last month, Suzanne Zick, who lives in Magnolia, Tex., a small
town northwest of Houston, called the E.P.A. and her state’s
health department to find out what she should do about the salmon-colored
granite she had installed in her foyer a year and a half ago.
A geology instructor at a community college, she realized belatedly
that it could contain radioactive material and had it tested.
The technician sent her a report indicating that the granite
was emitting low to moderately high levels of both radon and
radiation, depending on where along the stone the measurement
“I don’t really know what the numbers are telling
me about my risk,” Ms. Zick said. “I don’t
want to tear it out, but I don’t want cancer either.”
The E.P.A. recommends taking action if radon gas levels in
the home exceeds 4 picocuries per liter of air (a measure of
radioactive emission); about the same risk for cancer as smoking
a half a pack of cigarettes per day. In Dr. Sugarman’s
kitchen, the readings were 100 picocuries per liter. In her
basement, where radon readings are expected to be higher because
the gas usually seeps into homes from decaying uranium underground,
the readings were 6 picocuries per liter.
The average person is subjected to radiation from natural and
manmade sources at an annual level of 360 millirem (a measure
of energy absorbed by the body), according to government agencies
like the E.P.A. and the Nuclear Regulatory Commission. The limit
of additional exposure set by the commission for people living
near nuclear reactors is 100 millirem per year. To put this
in perspective, passengers get 3 millirem of cosmic radiation
on a flight from New York to Los Angeles.
A “hot” granite countertop might add a fraction
of a millirem per hour and that is if you were a few inches
from it or touching it the entire time.