At NAFTAL’s Carburants Branch, I participated in quality assurance of fuels across distillation, chemical, and physical testing. I conducted density (ASTM D1298), vapor pressure (D5191), distillation (D86), pour point (D97), cetane index (D976), and flash point (ISO 2719) analyses. Results were benchmarked against international limits (e.g., sulfur <10 mg/kg) to ensure environmental and safety compliance. I contributed to sampling protocols, data logging, and corrective actions for off‑spec batches. The internship highlighted the interplay between laboratory practices and large‑scale fuel distribution logistics.