Trichloroethylene poisoning prevention and treatment

1. Brief description

Trichloroethylene (molecular formula C2HCl3) is a colorless liquid with a chloroform-like odor and a boiling point of 87°C. Insoluble in water, soluble in organic solvents. Reacts violently with certain metal powders (eg aluminum, magnesium, titanium, tantalum, etc.). In the presence of moisture, the light will slowly decompose to form corrosive hydrochloric acid. When in contact with hot surfaces or flames, it can decompose to produce phosgene, toxic hydrogen chloride and corrosive fumes. The explosive limit in the air is 8% to 10.5%.

2. Exposure and health hazards

Trichloroethylene is widely used in the industry as a cleaning agent for the removal of oil stains on metals, glass and electronic components, as an extractant for oils and paraffins, as a solvent for resins and rubbers, as a dry cleaning agent for clothes, and as a refrigerant and disinfectant. Insecticides and fumigants are used in the manufacture of raw materials as well as in the preparation of pesticides. There are opportunities for access in occupational activities such as the manufacture, application and storage of trichloroethylene.

Trichloroethylene can be absorbed through the respiratory tract, digestive tract, and the skin. The main route of exposure to industrial exposure is the respiratory tract. Trichloroethylene is an accumulation of anaesthetic and has a strong inhibitory and anesthetic effect on the central nervous system. It also has toxic effects on peripheral nerves, liver, kidney and heart. A small number of contacts can also have severe allergic skin disorders.

3. Clinical manifestations

Trichloroethylene poisoning is mainly caused by acute poisoning. The symptoms of chronic poisoning and acute poisoning are similar, but only to a lesser degree. In occupational activities, exposure to a large amount of trichloroethylene in the short term can cause systemic diseases that are mainly manifested as central nervous system damage. The incubation period after exposure is from tens of minutes to several hours, and dizziness, headache, fatigue, facial flushing, and irritation of the eyes and upper respiratory tract may occur. Normally, it may return to normal within 24 hours after disengagement. However, in extremely high concentrations, it can quickly become unconscious without premenstrual symptoms.

(1) Mild inhalation poisoning

In addition to the above-mentioned forefoot symptoms, mild disturbances of consciousness (darkness, drowsiness, or paralysis) can also be present. In addition, facial trigeminal nerve damage can occur with mild liver or kidney damage.

(2) Severe inhalation poisoning

In addition to some of the above symptoms, the main manifestations are severe disturbances of consciousness (deafness or coma), two or more pairs of cranial nerve damage, and severe liver, kidney damage, or heart damage.

4. Principles of treatment and other disposal

(1) On-site rescue

In the event of acute inhalation poisoning, the poisoned person should be quickly removed from the scene, removed from the contaminated clothing, and thoroughly wash the contaminated skin with soapy water or clean water.

(2) Treatment principles

1 stay warm, close observation of the condition. The contact responders were observed for at least 24 hours and symptomatic treatment was performed according to the situation.

2 Because there is no special antidote, the treatment should be based on symptomatic and supportive therapy, and actively prevent brain edema and heart, liver and kidney damage. Heartbeats and respiratory arrests require rapid heart, lung, and brain resuscitation.

3 Avoid using epinephrine and other adrenergic drugs.

(3) Other disposals

Mild poisoning can be restored to the original work.

Severe poisoning should be removed from the operation of trichloroethylene.

5. Prevention, safety and labor protection

1 Improve equipment and processes to prevent smoke. Strengthen the ventilation of the plant, strengthen the production safety and personal protection knowledge training education.

2 Do a good job of fire prevention and explosion protection to prevent the static charge from accumulating and sparking (it can be grounded). When surrounding the fire, use a variety of fire extinguishing agents, and spray water to keep the barrels cool.

3 Do a good job in storage and transportation safety: Keep it dry and dark during storage and transportation. Ventilate along the ground and store separately from metals, alkalis, food and feed, and transport them separately.

4 Strictly control the concentration of trichloroethylene in the air of workplaces below the national labor hygiene standards (time-weighted average allowable concentration 30 mg/m3, short-term exposure allowable concentration 60 mg/m3).

5 Do personal protection: Use respiratory protection equipment, use protective gloves, and use safety goggles. Eating, drinking, and smoking are prohibited during work.

6 Workers must undergo a physical examination before taking up their posts. Each year, physical examinations are performed once. Any person who is diagnosed with an allergic constitution, or has organic diseases of the nervous system, obvious heart, liver and kidney diseases, and fundus lesions, should be prohibited from or out of the hazards of trichloroethylene.