Maps, compasses, astrolabes, and calipers are among the early tools used by ocean navigators. In the modern era, these tools have been largely replaced by electronic and technological equivalents. Despite these early beginnings, it would take many centuries before global navigation at sea became possible.
Harmful Effects of Radon. 1  Radon is the second leading cause of lung cancer (diagram to the right) and a serious public health concern. 2  The primary adverse health effect associated with chronic exposure to radon is lung cancer (typically bronchogenic): -squamous cell carcinoma.
1 Statistics.  Radon is the leading cause of lung cancer in nonsmokers, and it is deadly. If you havenât tested for radon in your home, this odorless, colorless, invisible gas could be harming your family.here are, but no one, except in a few states where concerned citizens have convinced their legislators to pass radon laws, has enforced them. Chief among these laws is the Radon Abatement Act, passed by Congress in 1988.