Well-designed repertory grids can be used to monitor sensitive changes to the psychological impact of perceived offensive material, on individuals and on the cohort exposed to it over time. Where there's an alert to crossing a threshold, appropriate risk management controls can then be introduced swiftly and on a timely basis

My previous H&S role was in a law enforcement organisation - one of the depts dealt with highly disturbing paedophillic material. Over the years we fine tuned the support for the individuals concerned, largely as follows: - Pre-deployment psychological assessment - regular (mandatory) sessions with psychologists appropriately experienced in this area - education for both managers and staff in the potential effects of dealing with such material, and the early warning signs to look out for - role rotation, so that individuals were rotated periodically into other roles that did not involved dealing with the material. Even with all the safeguards in place, problems sometimes developed so vigilance is important. Also, don't forget admin staff/filing clerks. You could use these inteventions to a greater or lesser degree, depending on the nature of the material and the length of time that workers are exposed. Hope this assists.