The E Factor: fifteen years on

The purpose of this perspective is to review the effect that the E Factor concept has had over the last fifteen years on developments in the (fine) chemical industry and pharmaceutical industry with regard to waste minimisation and to assess its current status in the broader context of green chemistry and sustainability. We conclude that the E Factor concept has played a major role in focusing the attention of the chemical industry world-wide, and particularly the pharmaceutical industry, on the problem of waste generation in chemicals manufacture. It provided, and continues to provide, the impetus for developing cleaner, more sustainable processes.