The Dangers of Methane Gas Poisoning and Exposure
As a primary component of natural gas, methane is a relatively common gas, and it is especially prevalent in the petroleum extraction and refining industries. It is also found in landfills, coal mines, livestock facilities, and wastewater treatment facilities. Because of its prevalence, there is an always-present danger for workers in these industries for being exposed to methane or experiencing methane gas poisoning.
Characteristics of Methane Gas
Methane gas is naturally an odorless and colorless gas, which makes it particularly dangerous. Like carbon dioxide, it is a greenhouse gas that is also encountered in normal atmospheric conditions at a rate of approximately 2.2 parts per million (ppm). Methane that is used for commercial purposes commonly has an added odorant so that workers have a way of identifying a threat in the event of a gas leak.
Methane also occurs naturally in wetland areas through the anaerobic decomposition of animal and plant matter. It is highly flammable and can ignite at a relatively low temperature. It is combustible, and when pressurized, it also presents a risk of explosion even at low concentration levels between 5% and 15%. Similar to radon, methane can migrate and accumulate underground. Proper ventilation and testing are crucial for any workers and areas where methane may be present and/or accumulate.
Risks of Methane Gas Poisoning Exposure
Methane exposure, particularly when experienced in high concentrations, can lead to methane poisoning. While it is considered relatively non-toxic, its primary threat is that it functions as an asphyxiant, similar to the threat posed by carbon monoxide exposure. When inhaled, it displaces ambient air, thus depriving the body of oxygen needed to breathe. While low concentrations are generally not harmful, higher concentrations lead to less oxygen availability and a range of symptoms may be experienced, including:
- Rapid breathing
- Increased heart rate
- Clumsiness and dizziness
- Decreased vision, especially in low lights
- Decreased alertness
- Loss of memory
- Emotional responses
- Nausea and vomiting
- Fainting and collapse
Symptoms will become more severe as the concentration of methane increases, and the period of exposure becomes more prolonged. Mild exposure over a period of days or weeks can often show relatively few physical symptoms, but still, have a dramatic impact on overall mental health. Long-term effects can include lasting cardiovascular, respiratory, and neurological problems. Those who have been exposed are also at an increased risk of developing memory loss, depression, epilepsy, claustrophobia, and heart problems.
Symptoms also onset and escalate more quickly when physical exertion increases (due to the increased oxygen needs of the body during physical activity). Prolonged deprivation of oxygen that can occur with methane gas poisoning can also cause permanent damage to the brain and the heart.
Aside from the severe effects that occur when methane gas exposure displaces oxygen, methane poses few other health hazards for those who encounter it. It is not an irritant, although when in liquified gas form, direct contact can cause frostbite and tissue death to exposed skin. It is not a known carcinogen.
Responding to Methane Gas Poisoning and Exposure
Providing initial medical responses for those who are suffering from methane exposure or poisoning can be incredibly difficult, particularly if they have fainted and collapsed. The best response is to remove them from the area where they can get fresh air, but this should not be done by risking others to exposure. Anyone sent in to retrieve impacted workers should be wearing the proper protective equipment, including a self-contained breathing apparatus and fire-retardant personal protective equipment.
Once the individual has been safely removed to an area with no methane, they may be revived. Methods for this can include mechanically administered oxygen, automated external defibrillation, or cardio-pulmonary resuscitation. Individuals who have experienced severe exposure or poisoning may need to stay at a hospital or under the care of a physician until the full extent of injuries can be determined, and a treatment plan developed.
When skin or eye exposure has occurred, it is crucial to wash thoroughly with warm water and seek immediate medical attention. Do not use hot water in cases where frostbite has developed.
Safe Practices when Working with Methane
When working with methane, it’s crucial that all safe handling and storage guidelines are followed to ensure worker safety. First and foremost, all ignition and explosion threats should be eliminated from the immediate vicinity, and smoking should not be allowed in the area.
When methane may be present in a confined space, levels should be tested prior to entry and periodically reassessed throughout the duration of the work to ensure that proper oxygen levels are maintained. When methane is stored in a cylinder, it’s crucial to protect them from damage and keep them in an upright position. When kept in storage facilities, methane should be located in an area that is cool, well-ventilated, and out of direct sunlight and other ignition sources. If the risk of a methane leak may present itself at any time at a particular facility, such as a petroleum refinery, continuous mounted monitors may be the best method for catching a leak early.
If a methane leak is suspected, it’s crucial to evacuate the area immediately and isolate it so that nobody enters it without knowing the potential risks. Once the leak is repaired, the methane should be disbursed quickly through ventilation or by knocking it down with a fine mist.
Despite its relative non-toxic nature, methane presents significant health risks to individuals who may come into contact with it as a part of their daily job. Also, many companies are protecting their employees today by providing them with methane detection wearable devices. In the event that an individual is exposed to methane, a wearable device can alert the individual to remove themselves in an effort to prevent methane gas poisoning.
In addition to its high risk of flammability and combustibility, it also acts as an asphyxiant. Exposure and symptoms can range from mild to severe and acute to long-term depending upon its concentration and the length of exposure time. At high concentrations for a prolonged time, methane gas poisoning can be lethal. Proper handling and safety measures, including extensive testing, are crucial in minimizing the risk of worker exposure.