The Bush administration has long been accused of being in bed with energy companies.

In Denver, that now appears to be literally true.

Federal investigators say that employees at the Minerals Management Service, the agency charged with collecting some $10 billion a year in royalties on oil and natural gas, received gifts from industry executives and, in some cases, had sexual relationships with them.

Employees of the agency, a part of the Interior Department, also used cocaine and marijuana, investigators found.

"Our investigation revealed an organizational culture lacking acceptance of government ethical standards, inappropriate personal behaviors, and a program without the necessary internal controls in place to prevent future unethical or unlawful behavior," they said.

The investigation focused on the royalty-in-kind program—when producers give oil and natural gas instead of cash; the oil and gas is then offered for sale on the market. A third of the program's staff, or 19 people, were found to have socialized or accepted gifts from Chevron, Shell, Gary-Williams Energy, and Hess.

The gifts were food, drinks, lodging, golf, and skiing. Investigators said that most company representatives claimed to be unaware of federal rules prohibiting gifts to employees from companies doing business with the government.

A supervisor in the program in Denver received almost $1,000 in gifts from the energy industry. He also engaged in sex and drug use with subordinates, and on one occasion was seen snorting crystal meth off a toaster oven.

Employees told investigators that they "partied" frequently with oil and gas company representatives. Two employees who attended an industry-sponsored event got so drunk that they were put up in lodging provided by a energy company.

One marketing specialist acknowledged that she did have romantic relationships with two men from the oil industry. When asked if she had any other personal or sexual relationships with others in the industry, she asked investigators if they "had any emails or evidence with which to remind her, adding, 'I did date people.'"

The inquiries follow an investigation last year that found the program to collect oil and gas revenues to be flawed and rife with ethical problems, leading the government to be underpaid.