Working for Facebook can cause post-traumatic stress disorder (PTSD). The Financial Times recently received documents showing that Accenture, a global professional services firm that provides content moderation for Facebook in Europe, asked its employees to sign a waiver acknowledging that screening content for the social media company could result in PTSD.

Facebook claims that it didn’t know about or ask Accenture to distribute the waiver to moderators in Warsaw, Lisbon, and Dublin. But it is well aware that sorting through flagged content on the site can be bad for one’s health. Facebook is facing lawsuits in California and Ireland from former employees who say they’ve suffered severe psychological damage working as content moderators.

Content moderators aren’t talked about much — they’re part of the invisible workforce that makes modern digital platforms go. When we scroll through our algorithmically generated feeds, we don’t realize that these content streams are being managed by real people working tirelessly to ensure our screens remain (generally) horror-free.