The organisation estimates that 97 percent of Americans it tested for the study were contaminated by the ingredient, which has been linked to allergies such as hormone disruption and cell damage.
The organisation also says that a companion study published just a few days earlier also links the chemical to low birth weight in baby girls, whose mothers are exposed to the chemical during pregnancy.
Oxybenzone is an organic compound derived from benzophenone and is used in a wide spectrum of sunscreen products as a means of absorbing potentially dangerous UVA rays.
Dosage is regulated by the EU
However, concerns brought about by earlier scientific studies have led authorities in the EU to regulate that any sunscreen product containing a more than 5 percent dose of the ingredient should be labelled accordingly.
This is because studies have shown that the oxybenzone can penetrate the skin's dermal layer, where it can increase production of free radicals, leading to the production of photocarinogen.
Currently there are no such regulations in place in the United States.
Currently 588 sunscreen products use the chemical in the US
According to the EWG there are currently 588 sunscreen products on sale in the US that contain the chemical, alongside a number of other personal care products such as facial moisturizers, lip balm, conditioners and anti-aging creams as well as sunscreens.
The group actually names key sunscreen brands, including Hawaiin Tropical, Coopertone and Banana Boat, which all contain the chemical.
"The Food and Drug Administration has failed miserably in its duty to protect the public from toxic chemicals like oxybenzone in personal care products," the EWG said in a statement.
The statement also accused the FDA of delaying final sunscreen safety standards for nearly thirty years because of the interests of industry lobbyists.