If a cosmetic contains ingredients that are forbidden or restricted in america they may be rejected or detained at the border.

The use of certain ingredients is forbidden in the United States

Before exporting a product to America, the company should ensure all ingredients are FDA approved.

A FDA pre-marketing approval is not required for ingredients of imported cosmetics, with the exception of color additives. But, the use of certain ingredients is prohibited or restricted by FDA regulations.
If a cosmetic contains any of the following ingredients, it will be refused by the FDA and its sale will be forbidden in America.
Prohibited Ingredients

The usage of the following substances are prohibited in cosmetics sold in the United States:
  • Bithionol
  • Chlorofluorocarbon propellants
  • Chloroform
  • Halogenated salicylanilides (di-, tri-, metabromsalan and tetrachlorosalicylanilide)
  • Methylene chloride
  • Vinyl chloride
  • Zirconium-containing complexes
  • Prohibited cattle materials
Ingredients restricted by FDA regulation

The following are substances that may only be used in cosmetics under the restrictions set by the FDA regulations:
  • Hexachlorophene (HCP)
Due to its toxicity, this substance may only be used when other preservatives are not proven to be as effective. The concentration of HCP in a cosmetic may not exceed 0.1%. Its use is also prohibited in cosmetics meant for use on mucous membranes such as the lips, nose and eyelids. 
  • Mercury compounds
Mercury compounds may only be used in eye area cosmetics. Their concentration may not exceed 0.0065% of mercury calculated as a metal. It is only allowed when alternative preservatives are not available. 
  • Sunscreens in cosmetics
Sunscreens are classified as drugs by the FDA. Sunscreen ingredients are only allowed in cosmetics if they have nontherapeutic and nonphysiologic ends (for example, if they are used as preservatives). Otherwise, the product will be subject to the rules regulating the importing and sale of drugs in America.