200926 Freon asphyxiation and frostburns

Freon asphyxiation and frostburns
MARS Report 200926

Note: For convenience, refrigerant gases are still referred to as 'Freon', a chlorofluorcarbon, by ships' crews although modern substitutes may be different in composition and properties.

On one of our ships, the second engineer came to the engine control room and found it extremely warm. He went to check on the A/C compressors. Noting a loss of Freon in the system, he decided to check for leaks. Based on his previous experience, he checked the switchboard room first, as similar leaks had occurred there before. On entering the switchboard room he 'smelled' Freon gas and instantly started to feel dizzy. Fortunately, he managed to turn round and made it out of the room safely.

Having left the switchboard room, the engineer had to sit down in order to recover from the dizziness. After this near-miss, the room was entered with breathing apparatus, the source of the Freon leak was found, the system was isolated, the leak repaired and the room thoroughly ventilated.

On another vessel, a low level alarm of Freon in the refrigerator compressor was observed in the engine control room. The chief engineer decided to recharge the system, using a flexible hose linking a full Freon cylinder and the recharging valve located on the compressor. After recharging, he closed the supply valve on the cylinder, then closed the valve on the compressor and released the pressure from the hose.

After disconnecting the hose, the chief engineer observed that the recharging valve on the compressor was leaking. He decided temporarily to fit a threaded plug over the leaking valve to control the gas before a repair attempt could be made. He momentarily removed the leather glove he was wearing and while threading the plug, a jet of liquid Freon splashed on his left hand, causing severe frost burns. Fortunately the ship was in port, so he was taken for medical treatment ashore.

Root cause/contributory factors
1. Lack of procedures;
2. Inadequate situational awareness;
3. Poor risk assessment;
4. Failure to use personal protective equipment (PPE) properly;
5. Failure of the recharging valve spindle; or
6. Recharging valve not closed properly (due to hard turning of the spindle), which allowed Freon to escape.

Corrective actions
SMS procedures reviewed as health and safety hazards of refrigerant gases were not adequately addressed in the manuals.

Safety information
1. Any crew member, who discovers that there is a Freon leak must:

• Move to an area of fresh air and warn other crew members;
• Inform the chief engineer immediately;
• Open up windows and doors and ventilate the space using fans or blowers, if practicable;
• If he feels any unusual health effects, seek medical advice.

2. All crew members should be aware of the hazards which may be associated with handling of refrigerants on board.

3. Freon vapour is heavier than air and may accumulate in low-lying areas, at deck level, displacing oxygen and posing an asphyxiation hazard.

4. Odour is not an adequate indicator of the presence of Freon and does not provide reliable warning of hazardous concentrations.

5. Freons are generally non-flammable and non-combustible, however, when involved in a fire or in contact with heated surfaces (>480°C), Freons decompose producing hydrogen chloride, hydrogen fluoride, phosgene, and chlorine. All of these decomposition products are acutely toxic and are very hazardous even in low concentrations.

6. Freons are incompatible with perchloric acid, chromium trioxide, nitric acid, chemically active metals (such as aluminium and zinc), alkali metals (such as sodium and potassium); and alkaline earth metals (such as beryllium, magnesium, and calcium).

7. Freons generally have a low order of toxicity. However, exposure to relatively high concentrations (>100 ppm) may produce adverse effects on health. Possible exposure routes include inhalation, ingestion, skin and eye contact.

8. Freon vapour may cause irritation of the eyes, nose, throat, and mucous membrane at low concentrations. At high concentrations, Freon vapour may cause pulmonary oedema and neurological problems such as central nervous system depression, dizziness, headache, drowsiness, tremors, seizures, confusion, lack of coordination, loss of consciousness, and paralysis.

9. Inhalation of high concentrations may also result in temporary alteration of the heart's electrical activity. The sensitivity of the heart to the arrhythmogenic action of epinephrine will increase, causing irregular pulse, palpitations, or inadequate circulation. Deliberate inhalation ('sniffing') may cause death without warning.

10. At extremely high concentrations; several thousand parts per million (ppm), Freon vapour has the potential to reduce the amount of oxygen available for breathing, especially in confined spaces, which can lead to asphyxiation.

11. Skin contact with liquid Freon can cause frostbite. Repeated skin contact with Freon gas may also cause drying with rashes.

12. Chronic exposure to Freon may produce weakness, pain, and paresthesias (a sensation of numbness, tingling or burning) in the legs. Chronic fluorocarbon exposure has been linked with motor, memory and learning deficits. Long-term inhalation of high concentrations may also lead to abnormal liver function with hepatic lesions.

First aid

1. Eyes - If eye tissue is frozen, obtain medical attention immediately. If eye tissue is not frozen, immediately flush eyes with large amounts of water for at least 15 minutes, occasionally lifting the lower and upper eyelids. If irritation, pain, swelling, tearing, or sensitisation to light persists, obtain medical attention as soon as possible.

2. Skin - If frostbite has occurred, do not rub the affected area. Flush with water or remove frozen clothing from frostbitten area and seek medical attention immediately. Otherwise, immediately remove contaminated clothing and wash contaminated area with soap and water for at least 15 minutes. Seek medical attention, especially if redness, itching, or burning is evident.

3. Ingestion - If Freons are ingested, do not induce vomiting, as the hazard of aspirating the material into the lungs is greater than allowing it to progress through the intestinal tract. Drink one to two glasses of warm water and obtain medical attention if necessary.

4. Inhalation - Move the exposed individual to fresh air immediately. If the person is not breathing, give artificial respiration. If the person has difficulty breathing, give oxygen. Seek medical attention.

Safe handling
Best practices for the safe handling of refrigerants include:

1. Store refrigerants in a clean, dry area out of direct sunlight, where temperature that does not exceed 50°C;
2. Never pressurise refrigerant systems or vessels with air for leak testing or any other purpose;
3. Never tamper with cylinder valves or pressure relief devices;
4. Never reuse or recharge disposable cylinders;
5. Wear protective clothing such as gloves and eye protection when handling any refrigerant;
6. Avoid contact with liquid refrigerant because frostbite may occur;
7. Avoid exposure to vapours through spills or leaks;
8. Evacuate the area if a large spill occurs. Return only after the area has been properly ventilated;
9. Verify proper cylinder hookup to the system;
10. Check to be sure the cylinder label matches the colour code;
11. Open cylinder valves slowly;
12. Avoid rough handling of refrigerant cylinders;
13. Do not perform any repair on pressurised equipment. Verify that the system has been completely evacuated with a vacuum pump before opening any lines;
14. Before welding or brazing, evacuate the equipment and then break the vacuum with air or nitrogen;
15. Always ventilate the work area before using open flames.