Mezue ahịrịokwu na-esonụ: Nsogbu ihi ụra na nsogbu ihi ụra zuru ebe nile, ha pụkwara inwe mmetụta dị ukwuu n'ahụ́ ndị ọ na-emetụta nakwa n'ụzọ akụ̀ na ụba nakwa n'ụzọ ndị ọzọ n'ahụ́ ọha mmadụ. US National Transportation Safety Board, dị ka Dr. Charles Czeisler, onye so na Institute of Medicine na Director nke Harvard University Medical School Division of Sleep Medicine na Brigham na Women's Hospital si kwuo, chọpụtara na isi ihe kpatara (31%) nke ihe ọghọm ụgbọ ala dị arọ na-egbu onye ọkwọ ụgbọala bụ ike ọgwụgwụ metụtara (ọ bụ ezie na ọ na-adịkarịghị ejikọta ya na nsogbu ụra, dị ka ụra apnea), na ọgwụ ọjọọ na mmanya na-aba n'anya dị ka ọnụọgụ abụọ (29%). Enweghị ụra abụwokwa ihe dị mkpa n'ihe mberede ndị dị egwu, dị ka
Mmanụ Exxon Valdez wụfuru, ihe mberede nuklia na Chernobyl na Three Mile Island na mgbawa nke ụgbọ mbara igwe "Challenger".