Ask your propane company about permits as they'll usually handle this aspect of the installation and file all required paperwork. You can also contact the city code compliance office to ensure that all necessary gas permits and requirements are adhered to before the propane tank installation takes place.
Basically, a hernia is a defect in the abdominal wall that allows intestine to poke through. If the hernia becomes incarcerated (the intestine becomes strangled), then a blockage and rupture of the bowel can occur. This is life threateneing. Many people survive, but are permanently disfigured. A perforated bowel can mean months in the hospital, large portions of the bowel being removed, etc.
Some diseases or defects can interfere with the way the organs do their jobs, causing pain. Crohn's disease can cause the wall of the intestine to swell and scar enough that it may block the intestine. Hernias can also block the intestines, as can growths like tumors. Torsion is a medical term that means twisting..