How to prevent acute poisoning and suffocation accidents in limited space

1. What are the characteristics of hazards in limited space operations?
1. Can cause death, is a high-risk operation.
2. The hazards in the limited space are completely preventable in most cases. For example, strengthen training and education, improve various management systems, strictly implement operating procedures, and provide necessary personal protective equipment and emergency rescue equipment.
3. Diversified forms of locations. Such as cabins, storage tanks, pipelines, basements, cellars, sewage tanks (wells), biogas tanks, septic tanks, sewers, fermentation tanks, etc.
4. Some hazards are hidden and difficult to detect.
5. Multiple hazards may coexist. For example, in the limited space, there is the danger of hydrogen sulfide, but also the danger of hypoxia.
6. Sudden in some environments. There is no harm when starting to enter a limited space for testing, but a large amount of toxic gas is suddenly emitted during the operation, causing acute poisoning.

2. What measures should be taken for limited space operations?
1. Before entering the job site, you must understand the site situation and past accidents in detail, and prepare detection and protective equipment in a targeted manner;
2. After entering the work site, first conduct oxygen, combustible gas, hydrogen sulfide, carbon monoxide and other gas detection in the limited space, and confirm that it is safe before entering;
3. Effectively isolate the electricity, high / low temperature and hazardous substances that may exist on the working surface;
4. Ventilation;
5. Wear isolated air respirator or oxygen alarm and correct filter air respirator when entering the limited space;
6. Wear effective communication tools and tie a safety rope when entering a limited space.
7. Equipped with guardians and emergency rescue personnel.
8. Strict safety management and implementation of operation permits.

3. What are the responsibilities of the person in charge of the production and management unit for limited space operations?
The main person in charge of the production and operation unit should strengthen the safety management of limited space operations and perform the following duties:
1. Establish and improve the safety production responsibility system for limited space operations, and clarify the responsibilities of the person in charge, operator and guardian of limited space operations;
2. Organize and formulate a special operation plan, safe operation procedures, accident emergency rescue plan, safety technical measures and other limited space operation management systems;
3. Guarantee the safe investment in limited space operation, provide safety protection facilities such as ventilation, detection, protection, lighting and personal protective equipment that meet the requirements;
4. Supervise and inspect the safety production work of the unit's limited space operation, and implement the safety requirements of the limited space operation;
5. Provide emergency rescue guarantee and do emergency rescue work;
6. Report production safety accidents timely and truthfully.

4. How to protect workers in limited space?
Before working in a limited space, first check the concentration of oxygen, dangerous substances, and harmful substances in the limited space; isolate electricity, high / low temperature, and hazardous substances; followed by ventilation; wear personal protective equipment and automatic alarm devices as required.
When an acute poisoning or suffocation accident occurs, emergency rescue personnel should carry out rescue only under the premise of personal protection and wearing necessary emergency rescue equipment. It is strictly forbidden to rescue rashly, causing unnecessary casualties.

5. What emergency rescue equipment should the production and operation unit equip?
The production and operation unit shall provide emergency personnel with:
1. Full-face mask positive-pressure air respirator or long-tube mask and other isolated respiratory protective equipment;
2. Emergency communication alarm equipment;
3. On-site rapid testing equipment;
4. High-power forced ventilation equipment;
5. Emergency lighting equipment, safety rope, lifeline and safety ladder, etc.

6. What is suffocating gas?
Asphyxiating gas is a gas that suffocates the body due to lack of oxygen. According to its different effects on people, it can be divided into two categories:
One type is called simple suffocating gas, which is non-toxic in itself, but due to their repulsion of oxygen, the body is hypoxic. Nitrogen, methane and carbon dioxide fall into this category.
The other type is called chemical asphyxiating gas, and its main hazard is to produce a special chemical effect on blood or tissues, which causes the oxygen transport and the tissue's function of using oxygen to cause tissue hypoxia. Such substances include hydrogen sulfide, carbon monoxide, hydride and so on.

7. What are the characteristics of hydrogen sulfide?
Hydrogen sulfide is a colorless, suffocating poisonous gas with smell of rotten eggs. It is a strong nerve poison and has obvious stimulating effect on the mucosa. Acute poisoning can occur at a certain concentration, and "shock-like" death can occur at very high concentrations. When the concentration of hydrogen sulfide is extremely high, it is odorless, the specific gravity is heavier than air, and it is easy to deposit on the bottom of pits, pools, and wells. Excavation and remediation of marshes, ditches, wells, sewers, tunnels, and removal of garbage, dirt, feces, and organic matter spoilage substances are very likely to be exposed to hydrogen sulfide.

8. The characteristics and prevention of carbon monoxide poisoning?
Carbon monoxide is a colorless, odorless, non-irritating gas, explosive, and is the most common harmful gas. Industries that are exposed to carbon monoxide include: metallurgy steelmaking, ironmaking, coking, forging and casting; chemical industry synthesis of ammonia, formaldehyde, methanol, acetone and oxalic acid. If these positions violate the operation regulations, accidents or pipeline leaks, the concentration of carbon monoxide in the operating environment may be too high and acute poisoning may occur.
Acute carbon monoxide poisoning mainly manifests as damage symptoms caused by acute cerebral hypoxia; a few patients may have delayed neuropsychiatric symptoms. Generally, mild poisoning will cause severe headache, dizziness, nausea, vomiting, general fatigue, and lack of energy. Severe carbon monoxide poisoning can cause shallow, moderate and deep coma, and severe death can result.
Prevention of carbon monoxide poisoning:
1. Do a good job in propaganda and education of workers who are exposed to carbon monoxide.
2. The point where carbon monoxide occurs should be closed to keep the workshop ventilated.
3. Before overhauling pipelines and entering high-concentration carbon monoxide sites, mechanical ventilation and natural ventilation should be used, and effective gas masks should be worn during operation.

9. How can citizens avoid poisoning accidents in limited space?
Citizens and friends are advised not to enter sewage, power wells, sewers and other underground space privately. If you want to clear the sewers and sewage wells, you should ask a professional team to work. When a poisoning and suffocation accident in a limited space is found in the community, the police should be called in time, and must not rush down to rescue. It is strictly forbidden to use open flames near sewage wells or pipelines with marsh gas, so as to avoid accidents such as explosions and combustion, resulting in casualties.