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¦.
Oral: primary immunization is 4 doses taken every other day for a week 1 week before possible typhoid exposure will be protected. Booster doses in 5 years. Im(injection): given x 1 - 2 wks prior to exposure will be protected. Booster dose in 2 years.