We prove the existence of the minimal speed of propagation c(*)(r, b, K) is an element of [2 root 1 - r, 2] for wavefronts in the Belousov-Zhabotinsky system with a spatiotemporal interaction defined by the convolution with (possibly, "fat-tailed") kernel K. The model is assumed to be monostable non-degenerate, i.e. r is an element of (0, 1). The slowest wavefront is termed pushed or nonlinearly determined if its velocity c(*)(r, b, K) > 2 root/1 - r. We show that c(*)(r, b, K) is close to 2 if i) positive system's parameter b is sufficiently large or ii) K is spatially asymmetric to one side (e.g. to the left: in such a case, the influence of the right side concentration of the bromide ion on the dynamics is more significant than the influence of the left side). Consequently, this reveals two reasons for the appearance of pushed wavefronts in the Belousov-Zhabotinsky reaction