This paper is concerned with the competition between recombination of a radical pair and radical attack on targets such as macromolecules or nanoparticles in solution, which are large on the molecular scale. The difference in scale between radicals and targets causes the kinetics to be transient over a long period. The specific novel feature of the analysis is the effect of the initial spatial correlation of the radicals on the kinetics of attack on the targets. The main results are (i) a simple modification of the Smoluchowski rate coefficient for scavenging and (ii) the probability of multiple hits on the same target. Both effects arise from the clustering of the radicals. The latter is of particular interest in radiation biology, because multiple hits result in complex damage. The analysis is validated against results from random flights computer simulation; excellent agreement is obtained.