Table 1: Texas counties detected with excess breast cancer mortality with statistical significance 1990–2001.

Potential Excess mortality	Annual Age-adjusted rates (per 100,000)	Year	Observed deaths	Expected deaths	Relative Risk (RR) of excess mortality	P Values	Total counties
Most Likely Cluster for non-Hispanic Whites (90% study period and 50%population at risk)	35.0	1990 – 1996	4088	3623	1.12	0.001	42
Secondary Cluster for non-Hispanic Whites	34.8	1990 – 1993	2240	1995	1.12	0.001	41
Primary Cluster for Hispanic White	29.0	1990 – 1998	1436	1212	1.18	0.001	127
Primary Cluster for Blacks (note: not statistically significant)	34.1	1991 – 1996	791	682	1.15	0.129	15