Basic procedures for on-site disposal of hazardous chemicals accidents

1. Establish a warning zone

After the accident, the warning zone should be established based on the spread of the chemical spill or the scope of the flame heat radiation. And the implementation of traffic control on major roads leading to the scene of the accident.

The following items should be noted when establishing a vigilance area:

(1) Warning signs shall be set on the boundary of the warning area, and there shall be special personnel to guard against it;

(2) Except for firefighting, emergency handling personnel and personnel who must keep their posts, other personnel are prohibited from entering the warning zone;

(3) When the spilled chemicals are flammable, the fire should be strictly prohibited in the area.

2. Emergency evacuation

Quickly evacuate personnel in the warning zone and contaminated areas that are not related to emergency response to reduce unnecessary casualties.

Attention should be paid to emergency evacuation:

(1) If the accident substance is toxic, it is necessary to wear personal protective equipment or adopt simple and effective protective measures, and have corresponding monitoring measures;

(2) It should be transferred to the side upwind, clear the special person to guide and escort the evacuation personnel to the safe area, and set up the post on the route of evacuation or evacuation to indicate the direction;

(3) Do not stay in low-lying places;

(4) To find out if anyone is left in the contaminated area and the fire area.

note:

In order for the evacuation work to proceed smoothly, each workshop should have at least two unimpeded emergency exits with obvious signs.

According to the toxicity of the accident substance and the designated hazardous area, the corresponding protection level is determined, and the corresponding protective equipment is equipped according to the standard of the anti-expansion level.

Classification of protection levels. See Table 1

Protection standards, see Table 2

1. Inquire about the situation of the distressed person, container storage, leakage, leakage time, location, form, diffusion range, surrounding units, residents, terrain, power, fire source, etc., fire facilities, process measures, and disposal opinions.

2. Use a test instrument to measure the leakage, concentration, and diffusion range.

3. Confirm the dangers of facilities, buildings and structures, and various hazards that may cause explosion and combustion, and confirm the operation of fire facilities.

At the scene of the accident, the chemical may cause harm to the human body: poisoning, asphyxiation, frostbite, chemical burns, burns, etc. When performing first aid, both the patient and the rescuer need appropriate protection.

1. On-site first aid precautions

â–¡ Select a favorable terrain to set up a first aid point;

â–¡ Do yourself and the personal protection of the wounded and sick;

â–¡ prevent secondary damage;

â–¡ At least 2 to 3 people should be collectively acted as a group to take care of each other;

â–¡ The rescue equipment used must be explosion-proof.

2. On-site processing

â–¡ quickly remove the patient from the scene to the fresh air;

â–¡ Give oxygen when breathing is difficult, perform artificial respiration immediately when breathing stops, and immediately perform cardiac massage when cardiac arrest occurs;

â–¡ When the skin is contaminated, remove the contaminated clothes, rinse with running water, and rinse them in time, thoroughly and repeatedly;

â–¡ When the head and face are burned, pay attention to the cleaning of the eyes, ears, nose and mouth;

□ When a person is frostbite, he should be rewarmed quickly. The method of rewarming is to soak it in 40~42°C hot water to increase the temperature to near normal. When gently massage the frostbite, be careful not to The skin of the wound is rubbed to prevent infection; □ When a person has a burn, the patient's clothes should be quickly removed, rinsed with running water, and covered with a clean cloth to avoid the contamination of the wound. Do not arbitrarily break the blisters. ;

â–¡ When the patient is thirsty, drink plenty of water or salty drinks.

3. Use special effects medication, symptomatic treatment, severe cases to the hospital for observation and treatment

note:

Before the first aid, rescuers should be sure that the injured person's environment is safe. In addition, mouth to mouth resuscitation and flush contaminated skin or eyes, to avoid further injury.

After the leakage of hazardous chemicals. It not only pollutes the environment, but also causes harm to the human body. In the case of combustible materials, it may also cause fire and explosion . Therefore, the leakage accident should be handled promptly and correctly. Prevent accidents from expanding. Leakage treatment - generally includes two parts of leakage source control and leakage treatment.

1. Leak source control

When possible, eliminate chemical spills or leaks by controlling the source of the leak.

Under the instruction of the factory dispatching room, the leakage source control is carried out by closing the relevant valves, stopping the operation or by adopting methods such as changing the process flow, material bypass line, local parking, circulation, and load reduction operation.

After the container leaks, take measures to repair and block the crack. Stopping further leakage of chemicals is critical to the overall emergency response . Success in plugging depends on several factors: the degree of danger near the leak, the leak hole size, actual or potential leak point pressure, leakage characteristics of the material. See Table 3 for the method of plugging.

2. Leakage disposal

The leakage of the site should be covered, contained, diluted and treated in time to ensure safe and reliable disposal of the spill to prevent secondary accidents.

There are four main methods for disposal of spills:

(1) Enclosure interception

If the chemical is a liquid, it will spread and spread when it leaks to the ground, making it difficult to collect and treat. To this end, the embankment needs to be intercepted or drained to a safe place. When fluid leakage occurs tank region, to close the rain valve to prevent outflow of material out along the groove.

(2) dilution and coverage

To reduce air pollution. Usually, a water gun or a fire hose is used to spray the misty water into the cloud of harmful vapors, accelerating the diffusion of the gas to the upper air and spreading it in a safe place. When using this technology, a large amount of polluted water will be generated, so the sewage discharge system should be dredged. For combustible materials, it is also possible to apply a large amount of water vapor or nitrogen to the site to destroy the combustion conditions. For liquid leakage, to reduce material into the atmosphere, evaporation rate, foam or other covering article can be used to cover the leaked material, forming the cover layer on its surface, to suppress evaporation.

(3) Containment (set)

For large leaks, the diaphragm pump can be used to pump the leaked material into the container or in the tank truck. When the leakage is small, it can be neutralized by sand, adsorbent materials, neutralizing materials, etc.

(4) Disused

The collected spills are transported to a waste disposal site for disposal. Rinsing the material with few remaining firefighting water, the flushing water discharged into oily wastewater treatment system.

3. Leakage handling precautions

â–¡ Personnel entering the site must be equipped with the necessary personal protective equipment;

â–¡ If the spill is flammable and explosive, the fire should be strictly prohibited;

â–¡ It is strictly forbidden to act alone during emergency handling. There must be guardians, and if necessary, cover with water guns and water cannons.

note:

When a chemical leaks, no one other than a specially trained person may attempt to remove the spill.

Hazardous chemicals prone to fire, explosion, but different chemicals, and when the fire broke out in different situations, rushed to save their methods vary widely, if disposed of improperly, not only can not effectively extinguish the fire, but the disaster will be further expanded. In addition, since the chemicals themselves and their combustion products are mostly highly toxic and corrosive, they are highly susceptible to poisoning and burns. Therefore, fighting a chemical dangerous goods fire is an extremely important and very dangerous job. Personnel and fire rescue personnel engaged in the production, use, storage and transportation of chemicals should be familiar with and master the main dangerous characteristics of chemicals and their corresponding fire-fighting measures, and conduct regular fire drills to enhance the resilience in emergency situations.

In case of fire, each employee should be well aware of their roles and responsibilities, grasp the content of the special requirements relating to fire protection, evacuation procedures and personnel of the fire hazardous chemicals.

1. Fire fighting countermeasures

(1) Fighting the initial fire.

Use a suitable mobile fire extinguisher to control the fire before the fire has expanded beyond control.

Quickly closed fire sites on the downstream valve, cutting off all the material into the fire place, and then immediately enable the various existing fire-fighting equipment, the initial fire extinguishing equipment and control the fire source.

(2) Take protective measures for surrounding facilities.

To prevent fire endanger adjacent facilities, cooling must take timely measures of protection, and rapid evacuation supplies by fire threats. Some fires may cause flammable liquids to flow out. At this time, sandbags or other materials may be used to intercept the flowing liquid or ditches to guide the materials to a safe place. With blankets, sea straws blocked manhole, etc. at the wellhead shade when necessary, to prevent the spread of fire.

(3) Fire fighting.

Fires that ban dangerous chemicals must not be blindly operated. The right fire extinguishing agent and fire fighting method should be selected for each type of chemical . If necessary, take measures to prevent leakage or prevent the expansion of secondary disasters. When the fire was controlled, people still have to send care, clean up the site, to destroy embers.

2. Fire protection precautions for several special chemicals

(1) Fighting liquefied gas fires, avoid blindly extinguishing fires, and must remain stable without taking measures to prevent leaks.

combustion. Otherwise, a large amount of flammable gas leaks out and mixes with the air, and when it encounters a fire source, it will explode, and the consequences will be unimaginable.

(2) For the explosion of explosives, it is forbidden to use sand to cover the pressure, so as not to enhance the power of explosives when exploding;

In the event of a fire, the water flow should be hoisted to prevent the strong water flow from directly impacting the stack, so as to prevent the stack from collapsing and causing another explosion.

(3) For fires that are wet and flammable, it is absolutely forbidden to use water, foam, acid and alkali and other wet fire extinguishing agents to save.

(4) The fire extinguishing of oxidants and organic peroxides is more complicated and should be specifically analyzed for specific substances.

Appropriate neutralizer dilute acids or bases in case of corrosive substances, the best modulation; (5) toxic chemicals and corrosion products fighting fire, should use low pressure water mist or water to prevent corrosive, toxic chemicals scatter neutralize.

(6) Flammable solids and spontaneous combustion materials can generally be saved with water and foam. As long as the combustion range is controlled, it can be extinguished step by step. However, there are a few methods for saving flammable solids and spontaneous combustion items. The 2,4-dinitrophenyl ether, dinitro naphthalene and naphthalene is easy sublimation of flammable solids, heated it emits flammable vapors can form explosive mixtures with air, especially in the chamber, knocking easily occurs, in Extinguishing From time to time, spray misty water over and around the burning area and eliminate all sources of ignition around.

note:

When the chemical fire, firefighters not to fire alone, exports should always be kept clean and smooth, to select the correct fire extinguishing agent should be considered when fire safety personnel.

The fire fighting of chemical fires should be carried out by a professional fire brigade. Other personnel should not act blindly. After the fire brigade arrives, introduce the material medium and cooperate with the firefighting .

Emergency process is not carried out step by step in the above order, but according to the actual situation as simultaneously as possible, such as hazardous chemical spills, leaks should be cut off at the same time as the alarm, and the like.

Chemical accidents are characterized by sudden, rapid spread, long duration, and wide coverage. Once a chemical accident occurs, it often causes people to panic. If not handled properly, it will cause secondary disasters. Therefore, companies should develop and improve emergency response plans for chemical accidents . Let every employee know the emergency rescue plan and conduct regular training to improve the ability of the employees to deal with sudden disasters, so that they will not panic, and they will not be chaotic, correct judgment, correct treatment, and enhance their self-protection awareness. reduce casualties.