In 1970, the chronic obstructive lung diseases (COLD) of bronchitis, emphysema, and asthma were the tenth leading cause of death in the United States. At that time United States mortality from emphysema had been increasing at the rate of 20-25 percent per year. In 1969 the death rate for COLD as a whole was 15.6 per 100,000 and that rate was considered to be only about one-half of all those deaths in which COLD was either an underlying or an important contributory cause. By 1986 COLD had risen to be the fifth leading cause of death in the United States with a death rate of 31.3 per 100,000.