Safety Tidbit #2.21 - Manganese
Sources: (a) Periodic Table – Manganese
Manganese is the fifth most abundant metal in the Earth’s crust. Manganese in the form of the black ore pyrolucite (manganese dioxide, MnO2) was used by the pre-historic cave painters of the Lascaux region of France around 30,000 years ago.
Manganese is a mineral naturally occurring in our bodies in slight amounts. The symptoms of manganese deficiency include high blood pressure, heart ailments, muscular contraction, bone malformation, high cholesterol, poor eyesight, hearing trouble, severe memory loss, shivers, and tremors.
Steel contains about 1% manganese, to increase the strength and also improve workability and resistance to wear. However, Manganese steel contains about 13% manganese. This steel is incredibly strong and used for railway tracks, safes, rifle barrels and prison bars.
Welding on steel can generate significant airborne levels of manganese fume. OSHA has set the ceiling limit of 5 mg/m3. A ceiling limit is that level that no worker should be exposed above at any time during the work day. However, getting instantaneous readings for manganese is very difficult. The American Conference of Governmental Industrial Hygienists recommends an 8-hour time-weighted average exposure level of 0.02 mg/m3 in the respirable fraction and 0.1 mg/m3 in the inhalable fraction of the particles.
Metal fume fever is a temporary condition caused by inhaling manganese fumes. Symptoms typically include chills, fever, upset stomach, vomiting, dryness of the throat, cough, weakness, and achiness. Manganism is a condition that occurs after exposure to toxic levels of manganese. Symptoms tend to mimic Parkinson's Disease and include gait disturbances, clumsiness, tremors, speech disorders, and psychological disturbances.
Although manganese is an essential mineral for our bodies, we don’t do well when we inhale it. Welding is the most common task where there is manganese exposure so industrial hygiene sampling must include manganese in the analysis. Standard control mechanisms include reducing the amount of time spent welding, adequate general ventilation but more importantly removing the fume at the point of generation by using portable (or installed) fume extraction systems.
Lastly, an employer must train all workers with potential manganese exposure as to the effects of the manganese on their bodies, how exposure occurs, and what precautions are necessary to ensure their safety.
I hope this information was helpful and thanks for reading my Safety Tidbits ~ Bryan
No comments:
Post a Comment