Two former Microsoft employees are suing the company for not protecting them from the psychological effects of viewing disturbing material.
The two men were left with Post-traumatic Stress Disorder (PTSD) after working at the firm, the lawsuit alleged.
Their jobs involved viewing and reporting material, communicated via Microsoft services, that had been flagged by automated software as being potentially illegal.
Microsoft told the BBC it disputed the claims, and that it offered industry-leading support.
"Microsoft takes seriously its responsibility to remove and report imagery of child sexual exploitation and abuse being shared on its services, as well as the health and resiliency of the employees who do this important work."
It said the balance of protecting internet users while minimising the impact on its employees was a continued learning process.
Saving children’s lives
Henry Soto and Greg Blauert worked for Microsoft’s Online Safety Team, a division responsible for upholding the firm’s legal obligation to pass on any illegal images to the US National Center for Missing and Exploited Children.
When an image is reported, or automated software has “spotted” an issue, a human being is required to view the material and forward it on to the authorities, a Microsoft spokeswoman said.
The company said people with this role are only required to do this particular task for a short period of time - and that they are kept in a “different office” from other staff..
But in papers filed on 30 December 2016, the two men said the company did little to warn or prepare them for the disturbing images they were required to view.
The lawsuit says both men’s efforts were “instrumental” in saving children’s lives and securing prosecutions, but that both were paying a serious psychological toll.
But the documents described Mr Blauert as suffering greatly from this work, contributing to a mental breakdown in 2013. When he expressed his discomfort, it is alleged that he was told to "smoke", "go for walk" or "play video games" as a distraction.