OSHA defines an excavation as any man-made cut, cavity, trench, or depression in the earths surface formed by earth removal. A trench is defined as a narrow underground excavation that is deeper than it is wide, and is no wider than 15 feet (4.5 meters). Dangers of Trenching and Excavation. Cave-ins pose the greatest risk and are much more likely than other excavationrelated accidents to result in worker fatalities.
How long does a typhoid shot last?   According to the CDC website, a booster dose is needed every 2 years for people who remain at risk.. The oral (live) vaccine lasts 5 years before another dose is neededâ¦.
1 According to a U.S. Centers for Disease Control and Prevention fact sheet, the oral vaccine provides immunity for five years, and the shot for two years. 2  Neither type of typhoid vaccine is 100 percent effective; both protect 50 to 80 percent of recipients. Side effects of the typhoid vaccine shot can include fever, headache or redness or swelling at the injection site; side effects of the oral vaccine can include fever, headache, abdominal discomfort, nausea, vomiting or, in rare cases, a rash.