Green’s Dictionary of Slang

a euph. for damn n.

1956		S. Selvon Lonely Londoners 95: Not giving a blast if they answer or not.
1959		S. Bellow Henderson The Rain King 49: What the blast is going on?
1976		A. Salkey Come Home, Malcolm Heartland 190: Meanwhile, not a blas’ goin’ on inside the country; nothin’ comin’.