Why is radon gas hazardous?

Usually lung cancer.

Explanation:

It causes cells in your lungs to be damaged, which can lead to lung cancer.

Usual symptoms include

persistent cough

coughing up blood

wheezing

shortness of breath

hoarseness

chest pain, especially when you cough or laugh

frequent infections such as bronchitis and pneumonia

Radon is part of the environment and generally isn't harmful. But long-term exposure to high levels of radon can put you at risk of developing lung cancer, especially if you smoke