在通风不良或封闭式的池、坑、井、罐、仓里,可能积聚着对人体有害的气体。它们是无形杀手,已成为我国四大伤害事故之一。1996年1～7月,全国此类事故6起,死亡31人。尤应引起重视的是,有18名工人是在同伴发生中毒的情况下,不带任何安全防护和救护用具,盲目下去救人而丧生的。一、有害气体中毒机理1.甲烷(CH_4)容许浓度空气中的含量达5％～15％时,遇明火会爆炸对人体的危害无色、无味、本身毒性很小(但它的化合物,如氯甲烷等毒性很大)。当空气中含甲烷量太高,而致含氧量相对减少,可引起间接性缺氧窒息。可能发生中毒的场所化粪池、下水道、污水井、沼气池、矿井、挖孔桩 Poorly ventilated or enclosed pools, pits, wells, tanks, and warehouses may accumulate harmful gases. They are invisible killers and have become one of the four major injuries in our country. From January to July 1996, there were 6 such accidents in the country and 31 deaths. Particular attention should be paid to the fact that 18 workers were killed and blindly rescued when they were poisoned by their peers without any safety protection and rescue tools. First, the mechanism of harmful gas poisoning 1. Methane (CH_4) allowable concentrations in the air when the content of 5% to 15%, the case of an open flame will harm the human body colorless, odorless, its own toxicity is very small (but its compounds, such as Chloro methane and other very toxic). When the amount of methane in the air is too high and the oxygen content is relatively reduced, it can cause indirect hypoxia suffocation. Sites where poisoning may occur: septic tanks, sewers, sewage wells, digesters, mines, digging piles