Twice each month, SAIF posts a photo on its Facebook page to encourage our “fans” to see how many safety hazards they can find. “Name that Hazard” has become a popular way to learn more about on-the-job dangers, but Illa Gilbert-Jones, SAIF senior safety management consultant, reminds us that some of the worst hazards cannot be photographed.
“One of the most significant safety hazards I ever encountered was one I couldn’t actually see,” she said. “It was in a copper smelter and, while there are certainly obvious, visible hazards posed by handling molten metal, there are invisible hazards as well. At excessive levels, substances contacting or entering the body may cause toxic effects that may be irreversible.”
Arsenic, cadmium, and lead fumes are just a few unseen dangers that require periodic industrial hygiene monitoring, engineering controls, and personal protective equipment. With these exposures, it is also important to track employee health.
“The chronic health effects of any of these metals can vary from metal fume fever to progressive respiratory disease and cancer. Acute exposures can be deadly,” said Gilbert-Jones.
Now that more smelters are being used to recycle electronic scrap metal like circuit boards, computer monitors, and consumer electronics, beryllium also is becoming a serious hazard.
Exposure to arsenic occurs through inhalation and ingestion, as well as through skin and eye contact. Chronic exposure can lead to skin disorders, including warts and pigmentation, as well as constriction of blood vessels. Acute exposures can lead to lung distress and death.
Cadmium can be found in paints, batteries, and phosphate fertilizers. The most serious consequence of chronic cadmium poisoning is cancer, usually lung or prostate cancer. Cadmium exposure can cause kidney damage and is believed to also cause anemia, loss of smell, tooth discoloration, pulmonary emphysema, and bone disease. Acute exposure can cause flu-like symptoms like weakness, fever, headache, chills, and muscular pain.
Lead can affect your health after several years, or after just a few days. The frequency and severity of symptoms increase with the concentration of lead in the blood. Common symptoms of lead poisoning are loss of appetite, nausea, vomiting, stomach cramps, difficulty sleeping, fatigue, headache, moodiness, and muscle aches. Chronic overexposure can result in severe damage to the blood-forming, nervous, urinary, and reproductive systems.
Some workers exposed to beryllium dusts or fumes may develop chronic beryllium disease (CBD), a slowly progressive respiratory disease characterized by the formation of lung lesions called granulomas. These granulomas impair the lungs’ ability to fully expand and to oxygenate the blood. There is no cure for CBD, although symptoms can be treated. Recent estimates indicate that as many as 134,000 U.S. workers may be exposed to beryllium.
If your workplace exposes workers to any hazardous chemicals, you must have a written hazard communication program and material safety data sheets (MSDS), ensure labeling is accurate, and provide information and training for employees. Exposure monitoring should also be conducted, and, based on those results, medical surveillance, periodic exposure monitoring, and regulated areas may be required.
Is there a difference?
Just in case you thought gases, fumes, and vapors were all alike
Most invisible hazards are in the form of gases, fumes, and vapors. Although these are similar, they are not the same. A gas is any substance that is gas at normal temperatures (any material can become a gas if the temperature is high enough). Vapors are formed when a liquid evaporates, and fumes are formed by the evaporation of solid materials, like metal during welding.
Some hazardous gases are classified as simple or chemical asphyxiants, meaning they can reduce the level of oxygen in the body to dangerous levels. This can lead to breathing difficulties or even death. Simple asphyxiants dilute or displace oxygen in the air, and chemical asphyxiants can either prevent oxygen from entering the blood or stop the normal transfer of oxygen from the blood to the tissues.
Simple asphyxiants include helium, nitrogen, hydrogen, and methane. Chemical asphyxiants include carbon monoxide, hydrogen cyanide, and hydrogen sulfide. Other gases, classified based on their specific toxic effects, include hydrogen fluoride, sulfur dioxide, phosgene, and ozone.
Fumes are made up of extremely fine airborne particles that are formed when solid materials evaporate. The metal fumes emitted during welding and smelting are examples of this.
Fumes can be harmful under certain conditions. When welding, the level of hazard depends on the welding method, the metal used, paints and other coatings on the metal, and ventilation. For example, fumes formed when welding galvanized metal or metal painted with lead-based paints can cause severe symptoms of toxicity rather quickly.
It is important to control the fumes with effective local exhaust ventilation or by protecting the welder with respiratory protective equipment.
The gaseous form of a substance that is liquid at normal room temperature or pressure is called a vapor. A liquid will change into a vapor and mix with the surrounding air through evaporation. A vapor can be changed back to the solid or liquid state by decreasing the temperature or the pressure. Examples include benzene, methyl alcohol, mercury, and toluene. Like fumes and gases, vapors are airborne and can become inhalation hazards.
Airborne hazards sometimes can be mixtures of all three (gases, fumes, and vapors). To protect your employees, provide local ventilation at the source to remove the material from the breathing zone. If that is not feasible or does not completely control the exposure, then respiratory protection must be worn.
For more information on carbon monoxide poisoning, see the December 2009 issue of Resource, Oregon OSHA’s health and safety newsletter.
You can find more information about toxic metals on OSHA’s website.
This article is from the fall 2011 issue of Comp News. See other articles from this publication.