In 2007, research conducted by the World Health Organization, Italian Istituto Superiore di Sanità, Consiglio Nazionale delle Ricerche and Campania Region collected data on cancer and congenital abnormalities in 196 municipalities covering the period between 1994 and 2002 found abnormally high disease incidence. These abnormal patterns may correlate to areas where there are uncontrolled waste sites. However, this work also highlighted the difficulty in determining causality and in establishing a link between increased death and malformation rates and waste disposal.
After the Senior and Mazza study, several other studies have been conducted to attempt to definitively link elevated cancer rates to waste exposure. A government-made waste-exposure index that classifies areas of the Campania region as high (5 on index) or low (1 on index) risk based on the type of wastes present in surrounding dumping sites, total waste volume greater than 10,000 cubic metres, and the likelihood of releases on water, soil and air was created. Statistically significant excess relative risks were found for several cancer types in the triangle of death, however, methods often struggle to account for lifestyle confounders such as tobacco consumption and occupation which could skew the results.
A US Navy study denied any real ill effects to on-base personnel while however advising their off-base personnel to drink bottled water citing polluted wells. The US Navy report denied any signs of nuclear waste dumping and instead related the traces of uranium to volcanic activity.