The organisation released its analysis last week of 23,000 products while international industry and regulatory representatives met in Brussels for a meeting to debate cooperation on cosmetics regulations worldwide.
The EWG claims that the FDA refused to allow consumer organisations to attend the meeting as part of the US representation.
The FDA claims it made the refusal because the Brussel's brief only specifed regulatory and industry representation, according to EWG.
Releasing its conclusions in a web-published protest letter to the FDA, the EWG claims that nearly one in 30 cosmetics sold in the US fails to meet one or more industry or governmental cosmetics safety standards.
The organisation also claims that there are 447 products on the US market that industry safety panels have found to be unsafe when used as directed.
The EWG has campaigned for greater public assessment of the safety of cosmetics in the US for many years.
In its latest research project the organisation claims to have found that 98 per cent of cosmetics contain ingredients that have not been publicly assessed.
The EWG also asserts that the Cosmetics Ingredients Review panel said that insufficient data meant that it was impossible to tell whether the ingredients in 1,331 products contain ingredients were safe for use in cosmetics.
"Cosmetics do not have to be approved as safe by the FDA before they are sold.
As a result, they too often contain dangerous ingredients banned in Europe and Japan or chemicals deemed unsafe for specific uses by their own industry scientists," said Jane Houlihan, an EWG spoke.
At the end of its letter to the FDA, the EWG called on the agency to ensure that personal care products on store shelves are safe.
It also said the FDA should give guidance as to whether it will consider as safe cosmetics that contain ingredients banned in other countries.
The EWG also asked for meetings regarding cosmetics safety policy such as the International Cooperation on Cosmetics Regulations meeting in Brussels on Thursday to be held in public.
Industry representatives have often been critical of EWG findings in the past.
In 2005 the EWG launched a web service called skin deep, containing safety information on 15,500 personal care products.
In response the Cosmetic, Toiletry and Fragrance Association stated: "This report is filled with erroneous information and false conclusions intended to mislead consumers.
There is no scientific evidence that any cosmetic product is anything but safe.
Cosmetics continue to be one of the safest categories of products used by Americans each day."