ENVIRONMENTAL ANALYSIS: Polychlorinated Biphenyls (PCBs): Industrial Miracle to Environmental Concern
In 1968, more than a thousand people in Yusho, Japan became sick after eating food cooked in PCB contaminated oil. This was the first time in nearly 40 years that PCBs were even considered to have toxic effects on humans. Since that incident, there have been disagreements over the health effects from PCBs. The one thing experts can agree on is that PCBs can be found almost anywhere.
A History of Concern
PCBs were first manufactured in 1929 and quickly became regarded as an industry favorite due to their nonflammability, chemical stability and electrical insulating properties. PCBs were used in hundreds of industrial and commercial applications including electrical, heat transfer and hydraulic equipment. PCBs also were used as plasticizers in paints, plastics and rubber products, in pigments, dyes and carbonless copy paper.
EPA estimates that more than 1.5-billion pounds of PCBs were manufactured in the United States before production was stopped in 1977. According to a study outlined in Environmental Pathways of Polychlorinated Biphenyls, approximately 24-million pounds of PCBs are still unaccounted for, and are believed to have been released into the environment. What's more significant is that PCBs have been found in nearly every biological species.
Why the Concern?
Laboratory animal studies show that PCBs indicate an oncogenic potential, which means they can cause tumors. However, much like the recent concerns about cellular phones and their link to brain tumors, not enough data exists to prove (or disprove) that PCBs can cause tumors in human beings.
EPA studies show that PCBs can be concentrated in freshwater and marine organisms, but a major concern is how they can impact the bottom of the food chain. PCBs can affect the productivity of phytoplankton, which is the primary food source directly or indirectly of all sea organisms. Phytoplankton also happens to be a major source of oxygen in the atmosphere.
As research continues, more potential sources of PCBs are being uncovered. And because laws to regulate PCBs already exist, industry must now focus on these new sources.
PCBs in Commercial Paints
By the 1950s, PCBs had become an established part of many exterior and interior paints and other coating formulations. PCBs were added to paint for various reasons, including water and chemical resistance. Chlorinated rubber paint was the most common paint to contain PCBs because it offered excellent water and chemical resistance, elasticity and durability. But because the chlorinated rubber alone caused the paint to be brittle, PCBs were added as a plasticizer (Painting the PCB Picture, Environmental Protection, October 2000).
Monsanto, who voluntarily ceased production of PCBs in 1977, developed a plasticizer known as Aroclor 1254, which became the plasticizer of choice when chemical resistance was desired. One particular formula called for 5.4% Aroclor 1254 by weight. Other paint and lacquer formulations typically specify 5 to 10% Aroclor 1254 that can lead to a dry weight of 15 to 25% PCBs.
Manufacturers used paints containing PCB plasticizers on many types of industrial equipment. Some equipment such as industrial furnaces and heat exchangers, is subject to temperature extremes. Other types of equipment include milling and grinding machinery that may have been manufactured (or painted) prior to 1979.
And while manufacturers clearly documented the use of PCBs as an ingredient of paint, few private or government environmentalists are aware of this issue. We have discovered concentrations of PCBs in industrial paints that far exceed EPA limitations. From hydraulic pump motors to lathes, PCBs were detected in both the paint and oils from existing reservoirs.
Scrapping or Selling Equipment
Although regulatory guidance is clear on what to do with known sources of PCBs, companies are not likely to test for it unless its known that the paint used on the equipment contained PCBs.
If plans are being made to upgrade equipment, there is risk involved with selling or scrapping old equipment. Equipment that dates to the 1970s should be sampled for PCBs and lead in the paint. Other potential sources of PCBs include oil reservoirs and sumps.
Disposing of such materials including "applied dried paints or other similar coatings or sealants" in a landfill is regulated under the Toxic Substances Control Act or TSCA (Code of Federal Regulations (CFR), Title 40, part 761).
Only a proactive policy for handling outdated equipment caught this potential environmental and financial risk. For more direction on how to handle the sale or disposal of old equipment, contact your local U.S. EPA regional office.