The United Nations, which urges the world’s companies to follow anti-pollution, labor rights, and other standards of corporate responsibility, often ignores those aims when investing its own $29 billion employee pension fund.

A copy of the world body’s investment portfolio includes at least a dozen companies that don’t adhere to principles in the U.N.’s “Global Compact” for corporate behavior, according to rights groups and pension managers who reviewed the list of almost 400 companies. Fund managers who screen for social responsibility say they would reject those dozen companies as assets in their portfolios.

One is London-based Rio Tinto Group, the world’s third-biggest mining company, in which the United Nations has a $22 million investment. The U.N. spent the past eight years working to end a civil war in Papua New Guinea that began over complaints about pollution from Rio Tinto’s copper mine on the island of Bougainville. Rio Tinto declined to comment.

“There are a lot of companies on this list that would not meet our criteria,” says Julie Gorte, director of social research at Bethesda, Md.-based Calvert Group, the largest American manager of a mutual fund that focuses on socially responsible investing. “I can tell that if they have any screen,it is extremely minimal and does not involve criteria such as indigenous peoples’ rights, human rights, product safety, and integrity.”

A former investment banker and U.S. State Department official appointed in May to the United Nations’ top management post, Christopher Burnham, says the pension portfolio is managed “not that much different than a bank.” He says the United Nations will hire a consulting company next year to review its strategy, including the question of whether to set new criteria.

In an interview at his U.N. office, Mr. Burnham said that while he “takes into account” a company’s environmental and labor practices, the world body’s “primary responsibility is to earn the highest return at the lowest risk” for the fund’s 142,245 participants and beneficiaries.

U.N. management practices are under broad scrutiny in the wake of investigations that turned up evidence of widespread corruption in an aid program for Iraq. World leaders who met in September in New York pushed for the United Nations to become more accountable.

Secretary-General Annan, who has encouraged closer ties between the U.N. and business throughout his almost nine-year tenure, in 2000 created a program to encourage companies to embrace 10 “universal” environmental, labor, human rights, and anti-graft principles. More than 2,400 corporate chief executives have agreed to adopt and promote the Global Compact aims.

The United Nations’ failure to make the principles a factor in investments erodes its credibility, attorney Karen Burstein, a former judge and New York state and city official and now a consultant to the U.N. Department of Management, concluded in a February report requested by Mr. Annan.

“The UN is in the intellectually problematic position of asking Global Compact partners to follow practices that it does not itself fully observe,” she said in an analysis of the compact’s role in investment strategy.

Calvert’s Gorte questioned the U.N.’s investment in Wal-Mart Stores, the world’s largest retailer, based on a lawsuit accusing the company of denying meal breaks to 115,919 current and former employees. The U.N. has $183 million invested in Bentonville, Ark.-based Wal-Mart, according to the portfolio list.

A Wal-Mart spokesman, Bill Wertz, said the company has “a very strict policy to pay our own associates for every minute they work.” A manager found to have violated the policy by not paying someone for overtime or breaks “would be subject to disciplinary action, including dismissal,” he said.

Four of the 10 Global Compact principles deal with labor standards, including one calling for recognition of the right to collective bargaining. Wal-Mart shut a Quebec store in April after it became the company’s first North American outlet to be unionized. The company said the store was unprofitable and the closure had nothing to do with the union.

The head of global warming policy at the U.S. offices of the environmental group Greenpeace, Kert Davies, says the U.N. shouldn’t have $275 million invested in Exxon Mobil, the world’s biggest publicly traded oil producer. Irving, Texas-based Exxon has been fighting the Kyoto Protocol, a U.N. treaty mandating reductions in emissions of “greenhouse gases” linked to global warming. The Global Compact calls for a “precautionary approach to environmental challenges.”

“It is ironic, to say the least, that a company that is this active working against one of the major U.N. treaties is this heavily invested by U.N. employees,” Mr. Davies says.

An Exxon spokesman, David Gardner, says the company’s opposition to the Kyoto Protocol “does not equate to a lack of concern about the environment.” He calls Exxon a “leader in advancing state-of-the-art pollution control technologies.”

Two companies in the portfolio – London-based Anglo American, the world’s second-biggest mining company, and Brussels-based Fortis, Belgium’s biggest financial-services company – were involved with rebel groups in the Democratic Republic of the Congo who were stealing the country’s diamonds, gold, and other natural resources, according to a 2002 report by a U.N. panel monitoring sanctions on the country.

Fund managers and rights advocates, citing violations of internationally accepted environmental, labor, and ethics standards, also questioned the portfolio inclusion of Archer Daniels Midland, Newmont Mining, and Phelps Dodge. Phoenix-based Phelps Dodge, the world’s second-biggest copper producer, paid $1.4 million in fines last year for what the Environmental Protection Agency said was the illegal discharge of 1,000 tons of sulfur dioxide at the site of an Arizona mine.

The Global Compact’s director, Georg Kell, says the United Nations can’t make investment decisions based on accusations and lawsuits filed against a company and must consider the sensitivities of all 191 member governments.

“For example, tobacco is a livelihood in many developing countries,” Mr. Kell says. “Many socially responsible investment funds are based on ethical orientations that are culturally oriented.”