Patient K., 36 years old, worker of varnish - paint factory, enrolled in the urology department with complaints of suprapubic dragging pain during and after urination. At cystoscopy in the right ureter found visible roughly villous papillary tumor. The mucosa of the bladder surrounding the tumor is moderately hyperemic and edematous. On the basis of survey diagnosed with bladder cancer. The patient was appointed a surgery. The carcinogenic factor may play a role in the occurrence of bladder cancer: