Although the nation's private and business foundations enjoy major tax exemptions and give away $2 billion annually, many operate largely in stealth and secrecy and refuse to make public the details of their operations, investments and beneficiaries, a new study charges.

The National Committee for Responsive Philanthropy also said the foundations give "startlingly small" amounts of money to newer charities concerned with minorities, women, consumers, the poor, the elderly, the disabled and the environment. Instead, they tend to pile their money into "long-established relatively well-known charities with very traditional approaches to social problems."

The committee's charges were made in a two-year study of the 208 largest foundations, whose assets account for $19 billion for the $34 billion in assets held by the nation's 21,500 foundations.

In the survey, the panel, whose board includes officers of the Consumer Federation of America, NAACP, National Black United Fund, National Organization for Women and National Council of La Raza among others, sought information on 22 key points. The committee said these were the results:

Thirty percent of the 208 foundations either failed to reply or declared they don't make public reports. The committee said the group included Chrysler Corp. Fund, Eastman Kodak Charitable Trust, Western Electric Fund, Olin Foundation, Newhouse and Annenburg Funds and the Gulf Oil Foundation of Delaware.

Twenty-nine percent provided some information but so little that the committee rated their response unacceptable. D.C.'s Cafritz Foundation and Public Welfare Foundation were in this group.

Thirty-seven percent were rated acceptable in providing public information.

Four percent were rated excellent -- led by the C. S. Mott Foundation of Flint, Mich. The others were Northwest Area Foundation, Bush Foundation, Dana Foundation, W. K. Kellog Foundation, Commonwealth Fund, Carnegie Corp. of New York and Rockfeller Bros. Fund.

Timothy Saasta, a committee official, said failure of many foundations to provide information on how to apply for a grant, the standards of judgement and objectives of the foundation made it hard for minority groups and individuals to apply for foundation money.

Although foundations must file some of this information with the Internal Revenue Service, and keep a copy of the filing in their main office for six months for public viewing, Saasta said access is still difficult. Those living outside Washington where reports can be viewed at IRS by appointment or the foundation's home city are mostly shut out.

Although the Cafritz Foundation received a "score" of 47 -- just below acceptable -- an official here provided a list of grants and instructions on how to apply. Neither document included information on investments, holdings, salaries and expenses, but the IRS document at the Cafritz headquaters included that.

The committee said most foundation grants go to schools and education and health groups, with virtually nothing to organizations of the poor, minorities or environmental movments.

For example, it said, a 1978 study of 153 foundations done by the Community Support Fund showed that in the Washington area, natural resources and environmental groups got nothing, consumer affairs groups got one-quarter of 1 percent, housing and neighborhood development groups got 2 percent. One private high school (St.Albans) received "more than the entire category of housing and neighborhood development."