Alien hunters and nerve agent contamination may be prompting Dugway Proving Ground to seek to expand its size.

Officials at the Army base are closed-mouthed about why they want to acquire a huge swath of adjacent land, mostly under control of the Bureau of Land Management. They have not even spelled out how much they want.

But they confirmed that the gigantic military reservation filed documents seeking approval for expansion studies.

The amount of land under discussion ranges from 55 square miles to 145 square miles — and if the nearby Dugway Mountains are included, that increases by 25 square miles.

One motive for acquiring land may be to keep Dugway's expected anti-terrorism training secret at a time when the base is coming under telephoto scrutiny by alien hunters.

Security hassles could grow as vexing for Dugway as they have been for many years at the military base at Groom Lake, Nev.

Groom Lake, also called Area 51, is 90 miles north of Las Vegas. It is famous in UFO lore as supposedly housing a crashed flying saucer. UFO fanatics have brought it under intense surveillance.

Top-secret military aircraft were developed at Groom Lake, including the U-2 and Blackbird spy planes as well as the Stealth fighter. The fact that no crashed saucers have been documented there hasn't deterred alien hunters from staking out the base with high-powered gear.

A few years ago, a rumor circulated that secret activities at Groom Lake had been transferred to Dugway. Now alien hunting is taking place just outside the Utah base.

One hunter-oriented Internet site is headed "Dugway Proving Ground — The New Groom Lake?" Located at www.abovetopsecret.com/pages/dugway.html, it displays an overhead view of Dugway facilities. "It is by far the most secretive facility in Utah as well as the most controversial," the caption reads.

Where was the picture taken? One vantage point would be from an aircraft, but airspace above Dugway is restricted. Another possibility is the view was snapped from a nearby mountaintop off base.

Among notes about mysterious vapor trails, increased military activity and unmarked black helicopters, the Internet site states: