Objectives This study analyzed the effect of living in the same household with a worker employed in an electrochemical factory on the hexachlorobenzene (HCB) concentrations of serum in the general population of Flix, Spain. Methods A total of 608 subjects from the general population (response rate 42%) completed a questionnaire about residence, occupation, life-styles, and medical history and provided blood samples. Among them, 412 had never worked in the electrochemical factory. Information about the occupation of the family members was completed, and the subjects were classified with the degree of relationship with the worker having been taken into account. A multiple linear regression analysis was conducted to model HCB serum for nonfactory workers. Results Having a spouse who worked in the factory was associated with elevated HCB concentrations in serum. The adjusted relative increases were 1.28 (P=0.0004) and 1.23 (P=0.0022) times the corresponding value of people not living with workers of the factory, respectively for spouses of current and past workers. Relatives other than spouses did not show any increase. Conclusions The results of this study suggest that, among nonworkers, living with a worker of the electrochemical factory in Flix is associated with an increase in concentrations of HCB in blood. These findings may suggest a source of exposure to HCB that has thus far not been studied and that could be important in populations not occupationally exposed to organochlorines.