Leakage accidents refer to the leakage of hazardous chemicals, toxic substances, and radioactive substances caused by the use, transportation, or human factors, resulting in large-scale air, ground, underground, water pollution, and casualties of people, causing major economic losses, social impact, and disruption of public order. event.
The disposal of leakage accidents is a difficult point in emergency rescue work for all types of accidents. Our firefighting response is to household gas, transmission and distribution pipeline leakage, production line leakage and road transport leakage. The fire fighting task is usually:
1. Immediately organize the rescue of the victim, organize the evacuation, or take other measures to protect other people in the area;
2. Quickly control dangerous sources and conduct inspections and monitoring of hazards caused by accidents to determine the hazardous areas, nature of hazards and levels of hazards.
3 , do a good job on-site cleaning, eliminate harmful consequences;
4. Find out the cause of the accident and assess the degree of damage.
First, the characteristics of leakage accidents
The characteristics of a major accident that occurs suddenly, spread rapidly, and has a wide range of hazards also determine that the rescue operation must be rapid, accurate, and effective. Therefore, the function of rescue work is to implement a hierarchical responsibility system under unified command, mainly in the region, and According to the development of the accident, take the form of a combination of self-rescue and social assistance, and give full play to the advantages and functions of the accident unit and the region.
The emergency rescue of leakage accidents is also a job involving a wide range of fields and is very professional. It is very difficult to accomplish by relying on a certain department, and it is necessary to organize the quantity of all aspects to form a uniform rescue command department and to unify the command. Under the command, the departments of security, rescue, public security, fire protection, environmental protection, health, and quality inspection should cooperate closely and coordinate their operations to organize and implement emergency rescues quickly and effectively, avoiding and reducing losses as much as possible.
Based on the specific toxic effects of chemical spills and their physical and chemical properties, the main characteristics of the chemical are determined as follows :
1 , easy to burn explosion
A large number of poisonous and harmful chemical substances are leaked, resulting in burning and explosion. The toxic gases produced can cause death or suffocation only by inhaling a few mouthfuls. Toxic gases can rapidly diffuse and penetrate into the air. General residents lack of protection against chemical accidents  The general knowledge and thoughts of nurses are prepared. Suddenly, there is a sudden and toxic effect. It is often impossible to take protective measures after an accident. Poisonous gases cause poisoning through the respiratory tract, eyes, mucous membranes, etc.
2. Rapid proliferation and extensive victimization
After a spill occurs, toxic and hazardous chemicals can spread through the air, roads, water sources and facilities. Poisonous and harmful gases can also spread with the wind, spread to several hundred meters or several kilometers in minutes or ten minutes, and the damage scope can reach several dozens of levels. Â Square meters to several square kilometers, causing poisoning;
3 , pollution of the environment, not easy to remove
Chemical poisoning can cause human skin, tissue, rottenness, difficulty breathing, convulsions, and coma due to its toxic effects. Some gaseous poisons cannot be seen or touched; Â (such as Hangzhou 6.4 phenol leakage accident, due to the impact of the incident coincided with heavy rain, resulting in part of the leakage of phenol with rainwater into the Xin'an River),
4 , the width involved, the impact is greater
Once a major chemical leakage accident occurs in a city, the contaminated areas need to be isolated and traffic must be blocked. It is necessary to mobilize large amounts of human and material resources.  Rescue, this will inevitably affect the city's comprehensive function. For example, the traffic arteries are forced to be regulated, and residents must evacuate and evacuated.  If the performance is disrupted, the production of the enterprise will be stopped, disrupted, or rebuilt, in addition to mobilizing the enterprise itself and the social forces in the region to rescue  In addition, the neighboring provinces and regions will also provide assistance in terms of material, financial, and human resources. Serious chemical accidents, besides involving all aspects of society, may also damage the reputation of the country and may also cause negative effects internationally. (As of 2005.11.13 , a leakage and explosion accident occurred in the nitrobenzene refining tower of the Shuanghua Plant of Jilin Petrochemical Company, resulting in 6 missing persons, 2 serious injuries, and more than 20 minor injuries.)
Second, the type of leakage accident
1. Leakage accidents of household gas and transmission and distribution pipelines;
2. Leakage accidents such as bottles, barrels and cans;
3 , road transport tanker leakage accident
4. Leakage accidents of production lines, flanges, pipelines, reactors (towers) and cooling devices;
5. Nuclear leakage accidents;
6. Other leakage accidents (artificial poisoning accidents).
Third, the basic procedures for the disposal of leakage accidents
1 , the alarm dispatched
According to the situation of the police, they will concentrate on mobilizing the necessary personnel and equipment, and request the superior commanding department to mobilize relevant forces as required, and rush to the scene safely and quickly.
Pre-estimate the nature of the event in the middle of the move
1. Keep in touch with the command center at all times during the move, and keep abreast of the specific conditions of the scene or nature of the incident;
2. If necessary, transmit the relevant information through the command terminal so that various preparations can be made in advance;
3 , for the on-site estimation and situation assessment, advance brewing or pre-deploy the rescue plan, put forward the precautions, let the war officers and soldiers entered the war on the ideological state "not to fight unprepared."
Fourth, special equipment
In addition to the principles of practicality, durability, and case, all professional rescue teams should timely sum up their experience and develop some simple and feasible rescue tools.
If there are not enough equipment and material guarantees, such as fire-fighting equipment, personal protective equipment, equipment for cleaning up spills, improper selection of equipment will result in serious injury to the emergency personnel or the nearby public, even if the emergency team is well-trained. Unable to alleviate emergency.
Fifth, inquiry reconnaissance
The first step in the accident handling is the initial assessment of the accident situation. The initial assessment should describe the on-site situation observed by the initial disposition staff within a few minutes after the accident. The initial assessment is the result of joint decision-making by the on-site commander and the disposer.
Before the accident handling action begins, the following information should first be collected:
(1) The type of chemicals being leaked;
(2) The location of the leak source;
(3) Description of the leakage process;
(4) The consequences of the leak;
(5) Whether the vapor cloud exists and its position;
(6) Whether the vapor cloud is flammable;
(7) Details of the wind direction under the steam cloud;
(8) Whether the leakage can be controlled;
(9) whether there is a fire source and the location of the fire source;
(10) Estimating control takes time;
(11) Whether additional assistance is needed.
In the vicinity of the accident site, attention should be paid to the discovery of precursory anomalies:
( 1 ) When a colored gas or liquid is found running, running, dripping or leaking, accompanied by strange taste.
(2) When the staff found a large number of simultaneous headache (halo), palpitations, boredom, difficulty breathing, vomiting, blurred vision, there is a sense stimulation, convulsions, cramps, and other symptoms faltering.
( 3 ) Animals have abnormalities, large numbers, and a wide range. E.g:
1) When many insects such as bees, flies, and butterflies are found to be unstable, shake their wings, and struggle.
2) When a large amount found frog, sparrows, pigeons, poultry, livestock, etc. blink occurs, scattered lag, sleep contraction, drooling, standing stability, dyspnea, cramps.
3) When many fish, shrimps, grasshoppers and other aquatic organisms are found to have accelerated biological activity and chaotic climbs, the activity is difficult.
4) Plant abnormality When the color of many kinds of plants is found to change.
When the above macro anomalies occur in these areas, it may be an early sign of chemical accidents.
The key to dealing with accidents caused by the leakage of hazardous substances is to identify the accidental substances. No substance can be taken before it is determined  Proper and correct action. The accident site commander of the initial assessment communicates with the operator to determine the contained substances and identify the cause of the accident. Knowing the cause of the accident helps dispose people to reduce or control the accident.
The toxic effects of chemical poisons on personnel are limited and constrained by various factors:
( 1 ) Poison physicochemical properties
Gaseous poisons are hazardous and have a wide range of hazards; the higher the gasification rate of liquid poisons, the greater the hazards of the base; and the harm of solid poisons is relatively small.
( 2 ) On-site meteorological elements
Meteorological elements mainly refer to the tiny meteorological conditions on the spot when a chemical accident occurs, such as temperature, humidity, wind direction, wind speed, rain and snow, and vertical stability. The high temperature makes it easy to volatilize poisons into vapors; high humidity (such as foggy days and rainfall) makes the poisonous gas difficult to spread; the direction of the wind determines the direction of gas cloud propagation; when the wind speed is 1 to 5 m/s , Â The poison gas cloud can spread, so the harm is the most full. If it is too slow, the poison gas is easy to be retained. If it is too fast, it may accelerate the damage of the diffuse surface of the poison gas cloud; the rain and snow can scour, dilute and cover toxic substances; vertical stability. refers to the temperature difference in the number of two different heights, with temperatures generally 2 meters high from the ground surface temperature is minus 0.5 m height from the ground is obtained, can be divided into: convection (hot on cold), inversion (under the cold and hot), isothermal (up and down almost equal) three situations.
( 3 ) Landforms
Topography and features can both shield poisons and change wind direction and wind speed, which can directly affect the direction and speed of the spread of poison clouds.
1. Poisonous air can pass from both sides or on the roof in case of an isolated low house;
2. In the case of a continuous arrangement of buildings, they can pass through the streets and the gaps;
3. In case of high-rise buildings, due to the large wind speeds on both sides, poison clouds can quickly pass through and spread;
4. When poisonous gas meets low-rise buildings, densely-ventilated streets and courtyards, enclosed houses, and poorly ventilated houses, toxic gases are most likely to be retained and the concentration of poisons is high;
The urban afforestation area can also slow down the spread of poisonous gas and allow poison gas to remain. Therefore, the rescue team cannot stop and residents should evacuate as soon as possible.
Sixth, protective
( 1 ) Determine the appropriate degree of protection based on the toxicity of the leaked item and the designated hazardous area.
( 2 ) Standards for classification of protection reference levels (see table)
Gas hazardous goods leakage accident protection reference level
Dangerous area Poisonous | Severe danger zone | Moderate danger zone | Mild danger zone |
Poisonous | One level | One level | Secondary |
High toxicity | One level | One level | Secondary |
Poisoning | One level | Secondary | Secondary |
Low toxicity | Secondary | Level 3 | Level 3 |
Microtoxicity | Secondary | Level 3 | Level 3 |
( 3 ) Reference Standards for Gas Accident Leakage Accidents (See Table)
level | form | Chemical protective clothing | protective suit | Protective mask |
One level | whole body | Built-in heavy chemical protective clothing | Cotton anti-static inner coat | Positive pressure air respirator or full-proof canister |
Secondary | whole body | Closed chemical protective clothing | Cotton anti-static inner coat | Positive pressure air respirator or full-proof canister |
Level 3 | Breathe | Simple protective clothing | Combat suit | Simple canisters, masks or masks, towels and other protective equipment |
Accident Command Establishment Location Selection:
( 1 ) Located in a ventilated area;
( 2 ) Determine the safety distance according to the wind direction;
( 3 ) Observe the accident to have a good vision;
( 4 ) There is sufficient space for emergency operations.
Seven detection
The detection of dangerous substances is actually the detection of accidents and causes of accidents. The first method is a small group of two people. Â Group away from (upwind in a higher position, and make sure they are not exposed to hazardous substances) the occurrence of the accident scene of the accident where the material was measured; the second method may be more dangerous and requires teams composed of two inspectors, To assess the condition of the accident area.
Things that need to be detected and understood include :
(1) The types and characteristics of the substances involved. For example, the flash point, calorific value, vapor density, vapor pressure, solubility, activity, pH, compatibility, the products of combustion.
(2) The amount of leakage, reaction, and combustion.
(3) The condition of the closed system, for example, the current pressure and temperature ( especially in abnormal conditions ) , the number and type of damaged containers , and the consequences of ongoing reaction leaks.
(4) The control level of the control system and the ability to convert, process, and neutralize.
VIII . Establishment of alert (establishing on-site operational area)
Another important task in the initial inspection and evaluation phase is to delineate a field operation area. In this area, it is clear that the disposing personnel can carry out operations and can count the personnel entering and leaving the accident site.
When determining the combat zone during the initial evaluation phase, it is mainly based on the hazards of the accident, weather conditions ( especially wind direction ) and location (the combat zone and personnel location are higher than the accident site ) . When setting up a combat zone, make sure there is enough room. The area needed at the beginning is larger and can be reduced if necessary.
The three types of operational areas established are: hazardous areas, buffer areas, and security areas.
Hazardous area: It is the area where the general staff is excluded and the place where the accident occurred. Its scope depends on the scope of the accident level and the execution of the clearance operation. Only disposal operators with special equipment (level 1 protection) can operate in this area. All personnel entering this area must work under the control of security personnel and commanders. You should also set up an emergency entrance that can be helped by emergency personnel in emergency situations.
Surrounding the danger area: It is the buffer area (light critical area), and it is also the area for purification and restriction passage. Here, the pollution will be purified, which can be called an entrance passage. Only secondary protection personnel can work here.
The third area is the safe area ( also called the support area ) : This area is the command and preparation area. It must be safe, and only disposal personnel and necessary experts can be in this area.
The third area is the safe area ( also called the support area ) : This area is the command and preparation area. It must be safe, and only disposal personnel and necessary experts can be in this area.
Sensory Method: According to the road surface, grass, trees attached to a layer of ice or water beads and drifting fog to determine the edge of the alert area. In addition, we can also judge the extent of diffusion based on the odors emitted in the air. For the above indications can only be used as a reference for the division of the warning area, used to adjust the scope defined by the law. The scope of adjustment generally follows the principle of "only large and small."
Detection method: The use of toxic and explosive gas detectors to determine the alert range is relatively accurate. The detector alarm value is generally set to about 20% of the lower explosion limit or dangerous concentration . The detector can detect the gas concentration in the critical area, and can also adjust the boundary between the medium- and low-risk areas through the alarm value. In the selection of detection points, it is not possible to address only the air above the ground or the low ground at the ground. If it is a road traffic accident, it should also carry out the inspection of the roads surrounding the accident. If the medium flows into the river, it should also be tracked in the direction of its tributaries.
The size, location, and scope of the restricted area will depend on the type of leak or accident, characteristics of the pollutant, weather, topography, terrain, and other factors. Real-time observations in the field, instrument readings, and various references can determine the size and extent of the controlled area. Transportation emergency guides, chemical accident emergency information systems, emergency preparedness guidelines, material safety data (MSDS), and other data and information compiled by the organization can also help establish control areas.
Other control areas may consist of on-site and off-site protection areas. For example, evacuation areas and shelters. Emergency plans should include the principle of evacuation or access to shelters. Special actions to modify or expand protective actions must be decided by the emergency commander. If the leakage is likely to spread outside the site, the commander should promptly contact the local government emergency department.
Nine , evacuation and rescue (protection actions)
The purpose of protective actions is to protect the lives and health of the public around and near the accident. These actions often include :
(1) Search and rescue operations;
Such actions are usually performed by ordinary firefighters. If personnel are injured, missing or trapped in downwind buildings and units, search and rescue operations need to be initiated.
Persons performing rescue operations should
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