Used primarily as an analytical reference standard in environmental testing laboratories to detect and quantify residues of endrin and related metabolites in soil, water, and biological samples. It plays a critical role in monitoring pesticide contamination and assessing environmental exposure. Due to its stability and defined chemical structure, it is suitable for calibration of instruments such as gas chromatographs and mass spectrometers. Also employed in research settings to study the degradation pathways of organochlorine pesticides. Handling requires caution due to its toxicity and potential environmental persistence.