Complex sentence: The plaintiffs in the subsequent litigation maintain that the pollution has resulted in an increase in cancer rates; apart from maintaining its lack of responsibility for the bulk of the pollution, Chevron has maintained that there is no causal link between the produced water and cancer.
Split into simpler sentences: The plaintiffs in the subsequent litigation maintain that the pollution has resulted in an increase in cancer rates. Apart from maintaining its lack of responsibility for the bulk of the pollution, Chevron has maintained that there is no causal link between the produced water and cancer.