The Sunscreen Project: Part 13.1 (Update further)

This is an addendum to the original article posted about sunscreen and sunblocks. I've just looked at some articles and discovered errors that I'd like to correct, as well as add some new information. Hence version 13.1!

First: OTC Sunscreen is regulated by the FDA (US Food and Drug Administration), not USDA (which is the United States Dept of Agriculture).

Here are some of the new regulations (in summary form):

Sunscreen should be reapplied every 2 hrs
"Broad spectrum" = covers both UVA and UVB
No more designation as "waterproof", "sweatproof", or "sunblock" - everything is now officially sunscreen only
Must be labeled as only "water-resistant" for 40 or 80 min before reapplying
This rule applies to OTC sunscreen as well as cosmetics and moisturizers with SPF
Maximum SPF value that can be labeled is 50+, because SPF higher than 50 has extremely low marginal yield (aka greater incremental protection)
Currently, the data about sunscreens in the form of spray isn't comparable to creams, lotions, etc

Other nuggets:

Don't apply adult sunscreens on kids and babies! Their skin is more sensitive to ingredients...
Don't store sunscreen in places that have direct sunlight, such as your car, open in the bathroom, near a window, or in the fridge with your food. It will make the active ingredients (and potentially other ingredients) break down faster.
The sunscreen ingredients that provide considerable protection against BOTH UVA and UVB rays are: dioxybenzone, menthyl anthranilate, oxybenzone, sulisobenzone, titanium dioxide.
The sunscreen ingredients that provide extensive protectino against BOTH UVA and UVB rays are zinc oxide, tinosorb M, and tinosorb S.
These two tinosorbs (listed in the previous bullet point) are actually both physical and chemical sunscreens - best of both worlds! Unfortunately tinosorb M and S are not yet approved by FDA so products with these are sold only in Europe and Asia. You can get them in certain sunscreens by Avene and Eucerin.