Tests of active and passive infrared sensor systems were conducted to determine the ability of these systems to detect petroleum oil on water. Since there are temperature and emissivity differences between oil and water it was expected that these systems would have applications for real time detection, alarm, monitoring, and recording of oil spilled or discharged in harbors, lakes, rivers, estuaries and coastal waters. Both sensors had distinct advantages. The active sensor provided absolute oil spill detection for ranges to 300 feet. The passive sensor makes possible oil volume determination, areal coverage, and probable oil detection for ranges to 1000 feet. Since both sensors have distinct advantages, a combination of thetwo is recommended. (Author)