N-Nitrosodi-n-propylamine (NDPA)

NDPA forms from the nitrosation of dipropylamine — a secondary amine present as an impurity in some herbicide formulations (particularly trifluralin, a widely used pre-emergent herbicide) and in some industrial processes [1]. The same general nitrosamine chemistry applies as with all N-nitroso compounds: a secondary amine (dipropylamine) plus nitrosating agents (nitrous acid, nitrogen oxides, nitrite) yields the nitrosamine [2]. NDPA has been detected in some cured meat products, particularly when dipropylamine-containing food additives are present alongside nitrite preservatives [1]. It is also produced as an industrial chemical intermediate and is detectable as a trace contaminant near certain chemical manufacturing and waste disposal sites [2].

People living near hazardous waste sites where NDPA has been disposed of or near facilities producing NDPA-containing herbicide products may face groundwater exposure [1]. Dietary exposure from nitrite-preserved processed meats containing trace NDPA has been documented in some markets [2]. Agricultural workers applying trifluralin-class herbicides that contain dipropylamine impurities may have skin and inhalation exposure [1].

NDPA undergoes alpha-hydroxylation by CYP2E1 to a reactive propylene oxide-type intermediate that alkylates DNA at O-6-guanine and N-7-guanine positions [1]. It induced esophageal tumors, nasal cavity tumors, and liver tumors in rodents. EPA classifies it as a probable (B2) carcinogen; IARC Group 2B [2].

Agricultural workers using NDPA-containing herbicide formulations [1]. Private well users near contaminated industrial sites [2]. Consumers of processed meats produced with nitrite and containing dipropylamine impurities [1].

1. Test well water if you live near former chemical manufacturing or hazardous waste sites [1]. 2. Reduce intake of heavily nitrite-preserved processed meats [2]. 3. Agricultural workers should use PPE when applying herbicide formulations and review SDS for NDPA content [1].