It is run by volunteers. They post relevant studies re: helmets with some commentary. They also have a good FAQ with pointers on how to inspect your helmet to know whether it is still safe and when helmets should be replaced.
The bottom line, which was new to me, was just because the helmet was “old” or “sweaty” doesn’t mean that it isn’t still useful. Some of the usual rules of thumb are more marketing than science.
After reading the faq I inspected all the helmets in our house and realized that my wife’s helmet really should be replaced…
Here’s a quick link to their page “When to replace a helmet”: