Meals are being shipped by the millions, but rivets are scarce. New uniforms and desert boots are in production - and in demand. Four months after President Bush ordered U.S. troops to the Persian Gulf, sustaining the still-growing deployment is proving to be an extremely complex, and costly, endeavor. More than $1.2 billion has been spent on food, clothing and medical supplies alone, never mind the millions more on weapons, parts and other materiel needed for the desert deployment. The operation is providing at least a temporary boom to many suppliers who were expecting less military business this year. Instead of closing plants or cutting shifts, several food and clothing suppliers are adding workers or offering overtime to meet Pentagon pleas for quick delivery. A sampling of the orders: -113 million meals, including 74.4 million Meals Ready-to-Eat, the basic field ration, 10.8 new entrees, including pot roast and beef sukiyaki, and 14 million new ``lunch bucket'' entrees to add chili and macaroni and cheese to the menu. -4.8 million pounds of sugar, 3.2 million pounds of flour and 1.4 million pounds of coffee, contracts worth a combined $5.6 million. -547,000 sundry packs, at a cost of $194 million, to supply the troops with razors, shaving cream, toothpaste and the like. -1.5 million tubes of lip balm, costing $278,000. -796,008 pairs of desert and hot weather boots, a $31.6 million deal. -379,375 cans of foot powder; 165,000 pairs of sunglasses; 371,000 wool sweaters; and 3.3 million desert camouflage uniforms, just one of several big-ticket clothing buys. -More than 600,000 armor-piercing rounds for the Army's Bradley Fighting Vehicles, a contract worth $14.3 million to GenCorp's Aerojet Ordnance Division. And buying is just half the task - the Pentagon has to get the goods 7,000 miles to Saudi Arabia and other Mideast points as it masses a 60-day or better supply cushion. The scope of the supply effort is giving pause to some military planners, who worry the inevitability of sustainment problems will be used to advance arguments for early use of force if Iraqi President Saddam Hussein ignores a Jan. 15 deadline to end his occupation of Kuwait. The operation is also expensive, and getting more costly by the week as stocks now filling Desert Shield requisitions run low, forcing the Pentagon to issue new contracts. So far, there have been only isolated shortages, officials say. Roughly 90 percent of parts orders are being filled from existing stocks, according to Defense Department figures. Scarce items rush-ordered from suppliers include rivets, electrical cable and strapping used to hold down pallets on military transport planes. Most orders are shipped by sea, but if a unit in the Mideast needs something in a hurry, it can turn to ``Desert Express'' - an emergency next-day delivery service the Air Force is running to Saudi Arabia from two U.S. bases. To date, ``Desert Express'' cargo has mostly been parts in short supply for tanks and planes, particularly Vietnam-era F4-G ``Wild Weasel'' anti-radar jets. The overall air leg of the supply line, operated by the Military Airlift Command, has made nearly 7,000 missions to the Mideast since August, carrying more than 200,000 passengers and 480 million pounds of cargo. The Navy's Sealift Command has delivered 28 billion pounds of dry cargo and nearly 6 billion pounds of fuel. As it orders more food, the Pentagon is trying to spice up the menu as a morale booster. That initiative meant a $44.6 million contract to George A. Hormel and Co. for sukiyaki, pot roast, spaghetti, lasagna and other dinners, and a $20.8 million deal for Dial Corp. for beef stew, chili, macaroni and cheese and other lunches. Other big beneficiaries are the Pentagon's clothing suppliers, who are rushing production of uniforms, the new line of desert boots and chemical protective clothing. Overall, more than 83,000 requisitions for $411 million in clothing have been processed for Operation Desert Shield.