Putting sunscreens full of chemicals onto your skin is just like eating them due to the absorption into the system.  It is important to look for and avoid ingredients in your sunscreen such as PABA, benzophenone-3, homosalate, diethanolamine, triethanolamine (DEA, TEA), octyl-methoxycinnamate, octinoxate, padimate-O, parsol 1789, parabens, insect repellent or DEET.  Many of these chemicals are toxic carcinogens, damaging to the DNA and/or disruptive to hormones.  

Are there any sunscreens that are safer to use?
I usually look for sunscreens with zinc oxide (or titanium dioxide) which are supposed to be safer for the body.  There is some concern about the toxicity of micronized or nanoparticles of zinc oxide or titanium dioxide.  So it comes down to choosing the product with the least harmful effect.  Obviously all of these items have some pitfalls to them, but for long time exposure in the sun I do use them.  A few companies I have found include:

Aubrey Organics (I also like some of their hair care and skincare products)

Badger Balm

Dr Hauschka

UVNaturalsUSA