Used primarily as a reference standard in environmental testing laboratories to detect and quantify polychlorinated biphenyl (PCB) contamination in soil, water, and biological samples. Its stable composition allows for accurate calibration of analytical instruments such as gas chromatographs and mass spectrometers. Due to its persistence in ecosystems, it is also studied to understand the behavior, degradation, and toxicological effects of highly chlorinated PCBs in the environment. Research applications include assessing bioaccumulation in food chains and evaluating remediation techniques for polluted sites.