LONE PINE, Calif. (AP) _ A Marine with one lung today neared the final leg of a 146-mile run from scorching Death Valley, the lowest point in the contiguous 48 states, to the summit of Mount Whitney, the highest point.

Maj. John Bates, 42, began his grueling trek at 8 p.m. Wednesday. He was expected to reach the end of the paved road and the start of the trail to 14,464-foot Mount Whitney before noon, forest Ranger Clark Trowell said.

Bates faced a 10.3-mile hike up a well-worn but extremely steep path to the summit. The steepest part of the trail is between 12,000 and 13,700 feet, where even the most experienced hiker struggles with the thin air.

The Marine ate salty foods, drank large quantities of water and took caffeine pills to stay awake but was suffering from cramps and nausea. Bates, who lost a lung to a bullet in Vietnam in 1966, said the run was for fun and to inspire other disabled veterans.

He planned to run nonstop, going from 282 feet below sea level to Mount Whitney's summit, in hopes of shaving five hours off the record of 45 hours, 15 minutes.

He appeared likely to break his personal best time: 63 hours, 12 minutes in 1986. He took two eight-hour sleep breaks during that run.

As his figure, blurred by heat waves, bobbed down the road Thursday, his wife, Stephanie, followed in an air-conditioned mobile home.

''I have been thinking about just yanking him into the car and driving home,'' she said. She begged her husband to eat more tuna sandwiches. ''They're a miracle cure - lots of salt.''

His run came during the hottest season for Death Valley, with the daytime air temperature often reaching 120 degrees and the sand 200 degrees, said Death Valley Acting Chief Ranger Russell March.