Transformers are essential components in power distribution. However, many older units still contain hazardous substances in their insulating oil that have long been banned: polychlorinated biphenyls (PCBs). Despite regulatory prohibitions in place for decades, these chemicals are still present in numerous ageing systems – posing significant risks to both the environment and public health. This article explores why PCBs in transformers remain an issue today and outlines available solutions for their safe removal.
What are PCBs – and why is it dangerous?
Polychlorinated biphenyls, or PCBs, are synthetic organic chemicals that were widely used in the electrical industry in the past. PCBs were especially common in transformers and electrical equipment, where PCB-containing oils were used to improve performance. PCBs are known for their high oxidation stability and excellent flame-retardant properties – seemingly ideal conditions for critical infrastructure.
However, the supposed benefits came with severe side effects: PCBs are extremely persistent, biologically non-degradable, and accumulate in the environment and living organisms. These chemicals are suspected to be carcinogenic and disruptive to hormonal systems. For these reasons, PCBs have been gradually banned in most countries since the 1980s.
Why were PCBs used in transformers – and why were they later banned?
Originally, PCBs were used in transformer oil to improve operational performance. Their resistance to heat and chemical breakdown made them attractive for use in electrical insulating oils. Sweden was one of the first countries to decide in 1989 to completely phase out PCBs. Similar legislation followed across Europe: The use of PCBs in new equipment has been banned for over 30 years.
However, PCBs were so widely used in the 1960s through the 1980s that they are still present in many older systems today. This means that many transformers still in operation contain PCB-contaminated oil – despite the well-known risks.
PCBs in transformers: How big is the problem today?
One might assume that PCBs in transformers are a thing of the past. But the reality is different: Across Europe, thousands of older transformers with PCB-contaminated oil are still in service. Especially, equipment dating from the 1970s and 1980s is likely to contain PCBs.
Regulatory requirements are now increasing the pressure to act: In the UK, for example, current legislation requires all transformer oil containing more than 50 ppm (parts per million) of PCBs to be taken out of service and disposed (incinerated) of by the end of 2025. Similar regulations apply in Germany and other EU countries. Operating transformers above 50 ppm PCBs are no longer permitted – both for health reasons and due to legal obligations.
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Why timely action is crucial to remove PCBs in transformers
As long as polychlorinated biphenyls (PCBs) remain inside a sealed transformer system, they pose no immediate threat to people or the environment. However, when transformers become leaky, are recycled, or need disposal, PCBs can enter the environment – and that’s when their harmful effects manifest. Improper disposal or uncontrolled release can lead to contamination of soil, water, and the food chain.
Therefore, proactive action is essential: Not only to meet regulatory deadlines, but also to prevent long-term environmental and health risks.
What solutions are available to remove PCBs in transformer oils?
The good news: Transformer operators have proven and safe solutions to remove PCBs from their equipment. A leading service provider in this field is Electrical Oil Services (EOS®). As specialists in transformer oils, EOS® offers comprehensive services for the disposal of PCB-contaminated transformer oils.
Regardless of the contamination level, the EOS experts can either organise for the oil to be incinerated. Alternatively, the company offers the option to regenerate the contaminated transformer oil by removing the PCBs using a specialised PCB-removal plant at their operation site in Stanlow, UK.
Important to note:
Due to stringent safety requirements, PCBs can not be removed from the oil at the transformer site by using a mobile regeneration. This means the contaminated oil needs to be removed from the transformer and brought to a specified production site. Electrical Oil Services (EOS®) offers a certified stationary process that meet the highest environmental standards.
How does the transformer oil change process work?
Transformer operators who suspect their equipment still contains PCB-contaminated oil should first conduct an oil analysis. Electrical Oil Services, for example, offers comprehensive insulating oil testing and advisory services for this purpose. If the transformer oil contamination is confirmed, EOS® arranges the safe removal of the contaminated insulating oil and ensures proper disposal or decontamination in accordance with legal requirements.
The insulating oil refilling and maintenance of transformer systems can also be managed by Electrical Oil Services - find out more here:
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Conclusion: Take action now to remove PCBs in transformers – before the deadline 2025 expires
Time is running out: By the end of 2025, transformer oil containing more than 50 ppm PCBs in Europe must be removed and destroyed (incinerated). Operators should not wait for regulations to force them to act – but take proactive responsibility for the environment, their employees, and their business.
Electrical Oil Services is your competent partner, ready to help safely and sustainably remove PCBs from transformers. Get in touch today – and make your equipment compliant, safe, and future-ready.
Do you have any questions? We will be happy to answer them. 
