The background swath fitting process is considered to fail if certain conditions apply pertaining to Pass 1 swaths (Appendix A). When this solution fails, the background solution is set to zero for the entire swath. If this occurs for an isolated swath, an interpolated solution from the two neighboring Pass 1 swaths is substituted for the original solution. If two consecutive Pass 1 swaths fail the background arrays for the entire image are set to zero and BCKGRD has ``given up'' on the image. This occurs for about 13 images in the GSFC high-dispersion archives, usually as a consequence of a major portion of the image being missing. This condition is documented in the processing history log.