OBJECTIVES The objectives of this program are: 1. To assess the potential for reduction of oxides of nitrogen (NOx) emissions from petroleum industry stationary combustion sources by application of existing@ demonstrated and emerging NOx control technologies. 2. To estimate total capital@ annual costs and cost effectiveness resulting from application of these control technologies. The scope of the program encompassed all land-based stationary sources in the drilling@ production@ gas processing@ liquid pipeline transportation@ and refining segments of the petroleum industry. The product of this undertaking is intended specifically for use in connection with API's ongoing participation in the nitrogen oxides proceedings underway at the U.S. Environmental Protection Agency and pursuant to the Clean Air Act@ as amended. This government proceeding@ calling for widespread public participation@ involves a review and possible revision of the existing long-term national ambient air quality standard for nitrogen oxides as well as the establishing of a short-term national ambient air quality standard for nitrogen oxides if available data support the need for such a standard.