A good overview of Far UV technology, including its efficacy and safety, has been published by Boeing.

Far UVC can autonomously and continuously eradicate viruses, bacteria, fungi, and allergens in occupied spaces, which is essential for containing and mitigating the continuous emerging threat of infectious diseases. What makes Far UVC unique from conventional Germicidal UV (GUV) is that its wavelengths often around 222nm, cannot penetrate the outermost nonliving cells in our skin and eyes. This significantly increases the areas we can safely deploy GUV, the most effective countermeasure against the dangerous pathogens often in the air and on surfaces all around us. Along with conventional GUV, effective diagnostics, vaccines, and therapies, the elimination of pathogens in occupied spaces is a critical element for the eradication of disease. Far UVC is an essential addition to existing sanitation practices, as part of a multi-pronged approach to prevent the spread of existing and emerging infectious diseases.