As monetization of risk becomes more mainstream, values must be assigned to the potential for human injury or fatality. The risk assessor need not generate values himself since such numbers are published in various sources. This includes values that have been used in US government decision-making for years.
Here is some example guidance: VSL Guidance 2013
https://www.transportation.gov/sites/dot.dev/files/docs/VSL%20Guidance%202013.pdf