21.   But no research has yet established how particles cause such illnesses, leading some critics to question the causal relationship.

22.   But parents of the stricken students, while acknowledging it may never be proven that the illness was caused by contamination, remain steadfast in exploring the possibility.

23.   But they have not quelled a debate over how much illness pollution causes.

24.   But this test detects relatively high levels of bacteria, while in some cases a low level of contamination can cause illness.

25.   But when passed from a mother to her baby just before birth, it can cause serious illness, even death.

26.   Diets that are rich in protein can eventually ruin the kidneys or cause serious illnesses like pancreatitis.

27.   Dow Corning vigorously denies that silicone causes illness and hopes to dispose of most of the future litigation with a single trial.

28.   Dow Corning, supported by a growing body of research, has denied throughout the battle that implants cause systemic illness like autoimmune disorders.

29.   E. coli is so virulent that even in minute amounts it can cause illness.

30.   E. coli are normal inhabitants of the human digestive tract, but only certain strains can cause illness.