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Are Solar Panels Hazardous Waste?

A worker cleaning the solar panel

Introduction:

Solar panels are the cornerstone of the future transformation of clean energy globally, as they power millions of homes and businesses. However, this green revolution has a challenge: the safe disposal of solar panels as they reach the end of their lifespan. U.S. is predicted to generate up to 1 million tons of solar panel waste, a serious concern about environmental safety and waste management. Some panels contain hazardous materials like lead and cadmium, raising the question: should these be classified as hazardous waste? Companies like Solar Cycle are stepping up with large-scale recycling efforts for solar panels, as they have recycled almost half a million panels in 2024 alone. Yet there is still a considerable risk of improper disposal, and existing regulatory frameworks remain fragmented and insufficient. Are you curious whether solar panels qualify as hazardous wastes and how this growing issue is being addressed? Read our blog post to know if whether solar panels are classified as hazardous waste and what the future holds for their disposal and recycling.

What Makes Waste "Hazardous" Under Federal Regulations?

The U.S. Environmental Protection Agency (EPA) under the Resource Conservation and Recovery Act (RCRA) defines hazardous waste as any material that threatens human health and the environment because of its chemical properties and origin.

The EPA classifies hazardous wastes on four characteristics: corrosivity, reactivity, ignitability, and toxicity.

What are Hazardous Waste Classification Criteria?

The hazardous waste should exhibit the following characteristics to be classified under the Resource Conservation and Recovery Act (RCRA).

1. Ignitability:

Waste is categorized as hazardous if it catches fire easily. These include materials with a 60°C below flashpoint. In solar panels, the components, such as the back sheet materials made from polymers (polyvinyl fluoride or polyethylene terephthalate), are particularly ignitable. When exposed to high temperatures, these plastic layers can ignite and contribute to fire hazard. Commonly, waste ignitability is tested through the Pensky-Martens Closed-Cup Test (Method 1010A) and the Setaflash Test (Method 1020B).

2. Corrosivity:

Waste with extreme pH levels (≤2 or ≥12.5) or that can corrode steel are categorized as hazardous Corrosivity issues in solar panels typically originate from internal elements like electrolyte solutions in built-in energy storage devices (such as lithium-ion batteries) or byproducts of chemical treatments performed during manufacturing (e.g., hydrofluoric acid or sodium hydroxide). If these chemicals leak or are disposed of inadequately, they can harm the environment and safety, particularly during recycling or landfill disposal. The pH elastomeric measurement test (Method 9040) or steel corrosion tests (Method 1110) are used to test the corrosivity of materials.

3. Reactivity:

Wastes are categorized as hazardous if they are unstable under normal conditions and can explode, react violently, and even release toxic gases such as peroxides and cyanide-containing wastes. Each waste is explicitly assessed to check its reactivity. Standard tests include Reactive Cyanide Screening Test (Method 9010C) and Reactive Sulfide Screening Test (Method 9034). Materials such as cadmium telluride (CdTe) and copper indium gallium selenide (CIGS) used in solar panels can release toxic gases like cadmium compounds or selenium fumes if the panels are damaged by fire, subjected to high temperatures, or improperly disposed of. Internal batteries or capacitors, if damaged or exposed to heat can react unpredictably and potentially dangerously.

4. Toxicity:

Wastes containing harmful agents like pesticides and heavy metals at dangerous concentrations are termed toxic/hazardous wastes. The toxicity of a waste is determined through Toxicity Characteristics Leaching Procedures (TCLP). Solar panels often contain heavy metals like lead, cadmium, and selenium, as well as arsenic and chromium which makes them potentially hazardous. These elements can leach into the environment if not disposed of appropriately, thus making the recycling and disposal of solar panels a serious environmental issue.

How do EPA and State-Specific Rules Govern the Hazardous Waste Classification?

The national RCRA standards are enforced by EPA in the U.S. However, the 49 states and territories are allowed to implement their own programs only when they meet or exceed the federal requirements.

California classifies solid corrosive materials as hazardous (beyond the federal liquid-only criteria).
Indiana instructs stricter waste determinations for generators, which demands audits and in-depth analysis.

EPA ensures that hazardous materials are safely managed by staying aligned with the RCRA's goals, reducing waste, and conserving resources.

Do Solar Panels Qualify as Hazardous Waste?

This is a complex question of whether solar panels qualify as hazardous waste under U.S. federal regulations. The answer depends on the solar panel types, composition material, and disposal condition. To find an answer, one needs to understand the detailed composition of solar panels, regulatory classification triggers, variability by panel technology, and testing methods to understand the hazardousness.

What Materials Are Solar Panels Made of and Are They Hazardous?

Solar panels are made up of multiple layers and materials, some of which may pose environmental risks or are hazardous in nature. Understanding their composition is key to assessing their potential classification as hazardous waste.

Silicon: The main semiconductor material is usually non-toxic. It forms the structural foundation of the solar panel.
Cadmium: Used in some thin-film panels (e.g., cadmium telluride, CdTe), is very toxic and has severe environmental and health hazards if it gets released.
Lead: used in soldering and electrical contacts of solar panels; is a notorious toxic heavy metal that can pollute soil and water.
Other Metals: such as copper, indium, selenium, and tellurium, employed in trace amounts for semiconductor layers and electrical contacts; are toxic depending on their concentration.

Cadmium and lead are particularly concerning in terms of and raise environmental contamination.

Does Hazard Classification Vary by Solar Panel Type?

Solar panel's classification as hazardous waste is dependent upon the panel technology:

Silicon-Based Panels (Crystalline Silicon): These are the most popular type in the U.S. market. They have lead in solder and other metals in small amounts. Most silicone panels do not exceed the hazardous waste thresholds.
Thin-Film Panels: These include the CIGS and CdTe-based solar panels. They contain cadmium and other heavy metals in higher concentrations. This increases the likelihood of classifying these solar panels as hazardous waste on the basis of the leaching test toxicity levels.

Therefore, thin-film panels are mainly categorized as hazardous waste, and their regulations are different from those of silicon-based panels, although both types need evaluation first.

What Conditions Cause Solar Panels to Be Classified as Hazardous Waste?

Solar panels can be classified as hazardous waste if the lead or cadmium levels reach harmful environmental levels. This classification generally applies under specific conditions which are mentioned below:

If solar panels are Broken, crushed, and damaged panels, they pose an increased risk of leaching, making them toxic or hazardous.
Panels that fail the Toxicity Characteristic Leaching Procedure (TCLP) Test indicate that the hazardous metals' levels exceed the EPA regulatory limits. The TCLP is a laboratory test with a defined standard created to replicate the leaching procedure in a municipal landfill, where trash is subjected to acidic environments over time. By simulating this environment, the test determines if toxic chemicals can seep into adjacent soil and groundwater with considerable potential for posing serious threats to public health and the environment. If a waste fails the TCLP, it is defined as 'hazardous waste' by the Resource Conservation and Recovery Act (RCRA) and must be managed, transported, treated, and disposed of by stringent federal and state hazardous waste guidelines.
Panels that are discarded rather than sent for proper recycling are also treated as per the hazardous waste rules.

If panels are sent to certified recyclers and meet the EPA's recycling rules, they might not be considered hazardous waste, regardless of whether they contain hazardous materials.

How to Responsibly Dispose the Solar Panels?

1. Classification and Handling of Waste:

Businesses must correctly assess whether the solar panels contain toxic substances and then follow regulations accordingly.

2. Hazardous Waste Compliance:

pIf solar panels are considered hazardous, they should be stored, transported, and disposed of by certified handlers according to the EPA and state regulations. Taking the services of certified recyclers helps to stay environmentally sustained and legally compliant.

3. Reporting & Documentation:

A detailed record should be kept regarding the panel testing, disposal, and recycling activities. However, some states need to report to environmental authorities in a formal manner.

4. Training for employees handling Solar Panel Disposal

Businesses should get proper training for the employees tasked to dispose of the solar panels. It is a serious job and taking it lightly can lead to serious environmental damage. You may hire certified experts to provide in-house training or get online Hazwoper Training and implement safe disposal processes customized to their requirements.

Conclusion

Solar panels power a greener future, but their end-of-life handling is as important as their installation. Although not all panels are dangerous, some, particularly older or broken ones, pose environmental threats when handled improperly. Companies must remain educated, test when necessary, and work with certified recyclers to stay compliant and sustainable. At HAZWOPER OSHA TRAINING, we are providing hazardous waste manifest training to help companies and recyclers understand the effective management of hazardous waste. Clean energy shouldn't leave a dirty legacy. Solar can be a genuine part of the solution using thoughtful planning and good disposal.