Before going down into a septic tank, manhole, sewage pit, vegetable cellar, fermentation tank or similar confined space, ventilate it first, get a passing gas test, and put protection and a watcher in place; if you can't, don't go in. If someone collapses inside, don't follow them down; call 119 (China's fire emergency number) and 120 (China's ambulance number)

Cost

Ventilation, testing, protection and a watcher all mean buying equipment or hiring people, and they take time. For cleaning a household septic tank, prefer a trained crew with equipment; ask the local service provider about the price. If you can't meet the conditions, don't go down yourself. The hard part is holding back from jumping in when someone has collapsed inside.

What you get

A “confined space” means a closed or partly closed place not meant for people to stay in long, such as a septic tank, manhole, sewage pit, cellar or tank. The Ministry of Emergency Management (应急管理部) analyzed the larger accidents in confined spaces in industrial and commercial enterprises since 2013. Poisoning and suffocation made up 96.8% of the accidents and 96.9% of the deaths. The main killers were hydrogen sulfide, carbon monoxide, nitrogen and carbon dioxide. Accidents where people rescued blindly without protection made up 87.4% of the accidents and 86.8% of the deaths. The Ministry's 2020 safety guidance handbook says that in nearly 80% of accidents, blind rescue made the casualties greater. More than 50% of the people who die in confined spaces are rescuers. In 2018 the State Council Work Safety Committee Office (国务院安委办) reported 8 accidents. In all 8, only 1 person was in trouble at first, and because of blind rescue each ended with 3 to 4 deaths. In 2019 at a paper mill in Dongguan cleaning a sewage pit, 3 people breathed in hydrogen sulfide and passed out. 6 people went down into the pit one after another to rescue them, and 7 people died in the end. In 2020 at a flour products factory in Jiaozuo, 1 worker fell into a material tank in the fermentation workshop. Others rescued blindly, and 6 people died in all. The U.S. National Institute for Occupational Safety and Health (NIOSH) investigated 70 confined-space fatal incidents from 1983 to 1993, with 109 deaths. Of those, 39 (36%) went in to rescue someone. Of these 39, only 4 were professional rescuers such as police or firefighters. Its 1986 alert said that about 60% of the dead were people who tried to rescue. The handbook says hydrogen sulfide smells like rotten eggs, but once the concentration is high, the nose can no longer smell it. At more than 1000 milligrams per cubic meter, it can kill within seconds. When carbon dioxide is high, a person passes out and collapses within seconds. The handbook requires that if the site is not equipped to rescue on its own, people promptly call 119 and 120, and “forced rescue is never allowed.” Pulling a person out from outside is only possible if the trapped person is wearing a full-body safety harness with the safety rope attached outside. Ministry of Emergency Management Order No. 13 requires industrial and commercial enterprises to “ventilate first, test next, work last.” Enterprises must provide testing, ventilation, protection and rescue equipment according to the risk, and monitors must be present throughout. During the work, ventilation and testing must also continue, and no one may enter if conditions do not meet safety requirements. Monitors must stop blind rescue without safety measures in place. The Anshun City Health Commission (安顺市卫健局) advises that when a vegetable cellar has been sealed for a long time, the vegetables use up oxygen and give off carbon dioxide. Before going down, open all the vents and ventilate thoroughly. This ventilation advice does not replace gas testing, protection and a watcher (China / U.S.)

Notes

Grade C is given because these are accident statistics and safety rules, and no study has calculated how many deaths following them would prevent. The size of the benefit is set at medium on judgment: the consequence is death, often several deaths at once, but it falls only on people who have to go into such places. What households run into is cleaning their own septic tank or biogas pit, and going down into a vegetable cellar or storage cellar to get things. Don't judge whether it is safe by smell; not smelling a bad odor does not mean there is no hydrogen sulfide. If you are told to go down a well or a pit at work, with no ventilation, testing, monitor or safety harness, you can refuse. For the basis for refusing, see §19.10 (you can refuse work with no protective measures). If someone has collapsed inside, first call for help and call 119 and 120; what you can do is open the cover from outside and blow air in. Once the person is pulled out, move them to fresh air, and if they are not breathing, start chest compressions; see §13.1 (someone is down and not breathing). The approach is the same whether the person who collapsed is a coworker, a neighbor or a stranger, for the same reason as in §13.25 (when you see someone drowning, don't go into the water yourself). For carbon monoxide from burning coal indoors, see §1.3 (carbon monoxide alarm). The beneficiary is mainly you, because the one who wants to go down and rescue is often you, and next the family members working with you.

Evidence grade

C : The author's experience or common practice, without direct literature.

Sources

1. Ministry of Emergency Management (2023). Interpretation of the Provisions on the Safety of Confined Space Operations in Industrial and Commercial Enterprises [in Chinese]. https://www.mem.gov.cn/gk/zcjd/202312/t20231212_471584.shtml
2. Ministry of Emergency Management (2023). Press Conference on the Provisions on the Safety of Confined Space Operations in Industrial and Commercial Enterprises [in Chinese]. https://www.mem.gov.cn/xw/xwfbh/2023n12y12rxwfbh/wzsl_4260/202312/t20231212_471598.shtml
3. Ministry of Emergency Management Order No. 13 (2023). Provisions on the Safety of Confined Space Operations in Industrial and Commercial Enterprises [in Chinese] (Articles 3 and 13 to 15). https://www.mem.gov.cn/gk/zfxxgkpt/fdzdgknr/gz11/202312/t20231208_471426.shtml
4. General Office of the Ministry of Emergency Management (2020). Safety Guidebook for Confined Space Operations [in Chinese] (Sections 2.1, 5.1 and 5.3, and typical accident cases). https://www.mem.gov.cn/gk/tzgg/tz/202010/W020201102332723879957.pdf (notice page https://www.mem.gov.cn/gk/tzgg/tz/202010/t20201030_371153.shtml)
5. Office of the Work Safety Committee of the State Council (2018). The State Council Work Safety Committee Office Circulates 8 Accidents in Which Blind Rescue Attempts in Confined Spaces Widened the Casualties [in Chinese]. https://www.mem.gov.cn/xw/bndt/201806/t20180608_229498.shtml
6. Ministry of Emergency Management (2021). Ministry of Emergency Management Releases a Batch of Typical Cases of Work Safety Accidents in Confined Space Operations [in Chinese]. https://www.mem.gov.cn/xw/yjglbgzdt/202103/t20210326_382087.shtml
7. Anshun Municipal Health Commission (2021). Beware of Carbon Dioxide Poisoning When Entering a Cellar [in Chinese]. http://wjj.anshun.gov.cn/wjgz/zsyd/202102/t20210223_66808351.html
8. NIOSH (1994). Worker Deaths in Confined Spaces: A Summary of NIOSH Surveillance and Investigative Findings (DHHS (NIOSH) Publication No. 94-103), p. 20, 22. https://www.cdc.gov/niosh/docs/94-103/pdfs/94-103.pdf (the original page has been moved to the CDC archive site, and the link is a web archive copy of March 8, 2023: https://web.archive.org/web/20230308204907/https://www.cdc.gov/niosh/docs/94-103/pdfs/94-103.pdf)
9. NIOSH (1986). Request for Assistance in Preventing Occupational Fatalities in Confined Spaces (DHHS (NIOSH) Publication No. 86-110). https://www.cdc.gov/niosh/docs/86-110/default.html (the original page has been moved to the CDC archive site, and the link is a web archive copy of June 11, 2023: https://web.archive.org/web/20230611112004/https://www.cdc.gov/niosh/docs/86-110/default.html)

Translated from the Chinese original. Original book, section 1, tip 46. This section is about health and medicines. It is general information, not a substitute for a doctor’s diagnosis or prescription. Content may be out of date and rules differ by place. When you actually deal with an agency, a doctor or a court, follow what local officials, doctors and lawyers tell you. Disclaimer