Mineral foundation is a type of makeup made from powdered minerals. You apply mineral foundation powder with a brush, using as little or as much as you need to even out your skin tone and ensure even coverage. Some brands of mineral makeup contain manmade chemicals that could be harmful to people with sensitive skin. If you experience skin irritation after using mineral foundation, stop using the product and talk to your dermatologist.

According to The Cosmetics Cop website, bismuth oxychloride is a common ingredient in many brands of mineral foundation. Bismuth oxychloride is a manmade powder that's created by combining bismuth--a byproduct of refining heavy metals such as lead and copper--with water and chloride, a compound derived from chlorine. Mineral foundation manufacturers add bismuth oxychloride to their products to give your skin a shimmery glow. The Green Beauty Guide website says bismuth oxychloride can cause skin irritation in some people who use mineral foundation. Judith Hellman, a dermatologist in New York, says bismuth oxychloride can aggravate acne and cause rashes in people with sensitive skin, especially people who suffer from rosacea.

Many brands of mineral foundation are made using mica, a natural forming mineral, according to the Dr. Oz Show website. The website claims that because the mica particles using in mineral foundation are so small, it's potentially harmful for you to inhale the tiny mica particles over time. Construction workers who use mica wear masks when working with the mineral to prevent inhaling mica fragments into their lungs. Mica inhalation has been linked to coughing, weakness and weight loss, according to the Occupational Safety and Health Administration.

Titanium dioxide offers powerful sun protection, which is why many makers of mineral foundation include titanium dioxide in their products. According to the organic cosmetics company Lavera, titanium dioxide is only safe in cream form and not in powdered form. The Organic Makeup Company's website says titanium dioxide powder becomes more toxic as it's processed into smaller particles. Because mineral foundation contains tiny nanoparticles of titanium dioxide, your skin can absorb titanium dioxide when you use mineral foundation. When titanium dioxide penetrates your skin, it can cause alterations to your skin's DNA.

Some brands of mineral foundation contain boron nitride, a manmade chemical that helps mineral foundation stick to your skin. According to ESPI Metal's website, boron nitride has been found to cause nasal irritation in lab rats. Prolonged exposure to boron nitride has been linked to weight loss and disruptions in the liver and kidneys.