The United States (US) became a World War II combatant, consumer products began to disappear from the market; from 1938 on, rearmament became a central concern. After Pearl Harbor, many leading sponsors had nothing to sell to the public. The making and selling of cars, refrigerators, washing machines, radios, television sets, and other equipment yielded to war production. Oil and gas were so strictly rationed that sales promotion was unnecessary, and seemed wrong. Senator Truman noted that the total costs of advertising, including costs of radio programs, television experiments, time purchases, agency commissions, and publicity, were being deducted by the sponsors as necessary business expenses. Why necessary, asked Senator Truman—when the US government was the sole customer? Donald M. Nelson, chairman of the War Production Board, said advertising was not necessary to do business with the government. Yet advertising funds were pouring into radio in increasing volume.