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.
Radon gas is radioactive, and as a gas, it is much more dangerous than a liquid or solid because it is airborne and can be inspired. If you breathe in radon and it undergoes r â¦ adioactive decay inside your lungs, there will be some heavy biological damage.adon is dangerous because it is a highly radioactive gas. Inhaling  it is known to cause lung cancer. You cannot see it, feel it, smell  it or taste it.