with different types of foam systems for structural firefighting and some have deployed front-line. apparatus with class A foam systems as an added tool in their firefighting arsenals. TYPES OF FOAM DELIVERY SYSTEMS. Class A foams consist of a mixture of water, foam concentrate, and air.
Skin Reaction from Vitamin D. I took a natural vitamin D3 supplement for several weeks and had a skin reaction on my back that slowly went away after I stopped taking it. There were no other variables that could have interfered at that time.
You have darker skin. Studies have shown distinct demographic differences in rates of vitamin D insufficiency and deficiency. Your skin pigment is natural sunscreen, says Holick. A sunscreen with 30 SPF reduces the skin's ability to make vitamin D by a whopping 97 percent, he says. Someone with very dark skin needs up to 10 times the amount of sun exposure than someone with a very pale complexion to make the same amount of vitamin D, he says. You're a big-time head sweater.