When you visit the Yucatan, it's a good idea to take some biodegradable sunscreen with you. Regular sunscreen can help kill coral reefs by promoting viral infections, and some places in the Yucatan, such as the Xel Ha water park only allow the biodegradable kind. It turns out that finding biodegradable sun block is harder than it looks. Most regular stores (I looked in Safeway, Longs, Lucky's and Costco) only sell regular sunscreen.

I finally found a biodegradable lotion at Grocery Outlet - Alba Botanica Fragrance Free Mineral Sunscreen SPF 18. I checked through the ingredients and none of them are in the lists that Xel Ha (at least) supposedly uses to check sunscreens. Beware that other Alba Botanica products do have parabens as preservatives, and those are not allowed. The lotion was only $3 for 4oz, so I rushed to get it, and indeed, it was probably a good idea given how expensive sunscreen can otherwise be.

But, but, but... as I began writing this posting, I did a bit of research and found that this sunscreen is not that good after all and that there are many that cause quite less damage to health and the environment. You can see a list of them here. Note that some of them are not necessarily biodegradable, but that, in itself, is not what kills coral reefs: specific chemicals are. Still, given that my regular sunscreen, Neutrogena Ultra Sheer Dry-Touch Sunblock, SPF-70 is much worse, I'm not too sad. Of course, the Neutragena stuff has a SPF of 70 and really works, and the Alba Botanica stuff only has 18, which means I'll have to apply thick layers of it and do it often.

I'm including here the list I've found of sunscreen ingredients not allowed at Xel Ha and similar parks:

4-methylbenzylidene
Benzophenone
Butil methoxydibenzoilmetane
Butylcarbamate
Butylparaben
Cetyl Dimethicone
Dimethyl Capramide
Ethylhexyl
Hexyldecanol
Homosalate
Methylparaben
Octinoxate
Octocrylene
Octyl salicylate
Octyl metoxycinnamate
Oxybenzone
Polyethylene
Propylparaben

Note that some places want oil-free sunscreens (which mine is not), but I have found no information that says that non-petroleum based oils damage coral reefs. After all, humans and fish both have natural oils in their skins.