The association between Total MWF (all types combined, cumulative exposure (mg/m3-yr)) and incidence of renal cell carcinoma (RCC) (A) among all subjects, (B) White males, and (C) Black males in the United Autoworkers-General Motors cohort, 1985–2009. Cox proportional hazards regression models using penalized splines controlled for age, gender, race, calendar year, year hired, plant and used time since hire as the analytic timeline. The solid horizontal line represents the null value. The rug plot along the bottom horizontal axis indicates the person-time distribution by exposure. Each spline was truncated at the 99th percentile of total MWF (A) all subjects (91.5 mg/m3-yr), (B) White males (93 mg/m3-yr), (C) Black males (99 mg/m3-yr).