Occupational asthma due to California red wood (Sequoia sempervirens) dusts.

Two patients with occupational asthma due to California redwood (Sequoia sempervirens) sawdust are described. They developed specific immediate and late asthmatic reactions after occupational-type exposure tests to this wood dust. In one patient the immediate asthmatic reaction was inhibited by pretreatment with disodium cromoglycate and atropine; however, the late asthmatic reaction was only partially inhibited by disodium cromoglycate and was not affected by atropine. Low molecular weight chemical compounds present in the redwood may be responsible for the symptoms.