We apply the method described above to the lost asteroid 1998 OX4. Attention was focused on this object after we announced that it has a remote, but not negligible impact probability. It was discovered on July 26, 1998 (UT) by Jim Scotti with the 0.9-m Spacewatch telescope on Kitt Peak [MPEC 1998-O27], and observed only over a short arc, due its intrinsic faintness and unfavorable observing conditions [MacMillan 1999]. The keplerian orbital elements with RMS uncertainty at epoch 1999 Jan 22.0 TDT are: semimajor axis AU, eccentricity , inclination degrees, longitude of ascending node degrees, argument of perihelion degrees, mean anomaly degrees. The object is already lost by several degrees, and the large uncertainty in semimajor axis implies that the length of the confidence region will continue to grow rapidly.