A high-ranking District of Columbia official was outraged. He had just received a piece of certified mail at home from the District of Columbia government that cost the city $2.45 in postage.

"I'm a taxpayer, too," the official told a vistor. "Why the hell couldn't they just bring it up to me, or notify me to walk down and pick it up?"

The official was one of an estimated 5,000 D.C. officials and employes who recently received similar brown manila envelopes from the Office of Campaign Finance, a semiautonomous arm of the D.C. Board of Elections and Ethics. The total postage bill ran to $7,000, since many envelopes cost less than $2.45 to mail.

What the envelopes contained were confidential personal financial statements-including copies of federal income tax returns-the employes had filed over the past four years. They were kept sealed, to be opened only if the employes were seriously accused of wrongdoing.

Now, made legally obsolete by a new D.C. law that prescribes a different form, the documents had to be returned to those who had filed them.

Despite the existence of an internal city mail system that serves 259 office buildings and schools, the campaign finance office chose to use the U.S. Postal Service.

"We had to do it the right way without any risk of them (the statements) falling into wrong hands-that would have been very bad," Lindell Tinsley, deputy director of campaign finance who is filling in as head of the office, said. "We had to maintain confidentiality."

Sam D. Starobin, director of the Ddepartment of General Services, which runs the city's own mail system, said there was no way he could have set up a receipt system comparable to certified mail.

"But I think they could have done something for a heck of a hot less than they spent," he said.