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Normal-anion-gap (hyperchloremic) metabolic acidosis is produced by loss of bicarbonate or impaired distal H⁺ secretion, as seen with proximal renal tubular acidosis, diarrhea, and pancreatic bicarbonate losses that can accompany severe pancreatitis. In contrast, salicylate poisoning typically causes a high-anion-gap metabolic acidosis (often mixed with respiratory alkalosis), not a normal anion gap disturbance [Buisman 2022, PMID 35971785; Kraut 2015, PMID 25852932].