Betty Galloway has been supporting herself and her teen-age son for three years by selling panty hose and belts from her vendor's table at the corner of Connecticut Avenue and K Street NW. But the District's new sidewalk vending rules due to take effect May 15 will ban the sale of such items and put her out of business, she says.

Galloway is among more than 200 sidewalk vendors who are angered by the new rules and who have joined a labor union, which filed suit yesterday in U.S. District Court to block implementation of the hotly debated regulations.

Officials of Local 82 of the Service Employees International Union said they believe their recruitment drive is the first time street vendors have unionized in a major city. An AFL-CIO spokesman said he knew of no other case in which vendors have joined a union.

The new rules will limit the number of vendors and the types of goods they can sell, and also will require wooden carts for nonfood vendors, who will be prohibited from selling outside an assigned vending spot. City officials said the rules will reduce sidewalk congestion, better protect consumers and improve sales tax collections.

The union drive and lawsuit are the latest chapters in protests by vendors who contend that the new rules are an effort by bigger businesses to stifle low-cost competition. The vendors also said they did not have sufficient chance to oppose the rules when the D.C. Office of Business and Economic Development enacted them last year.

"We are business people, but we are also laborers," said Kwasi Abdul Jalil, a vendor who said he organized the union effort because vendors lack the political and economic clout of groups such as the Board of Trade, which sought limits on vendors.

"We are the lower rungs of the social ladder . . . . We saw we could not fight the city government or fight the Board of Trade, so we sought help from the Service Employees."

The District has more than 5,200 licensed vendors, but the new rules will allow only 2,900 licenses in downtown and 1,310 in residential neighborhoods. The city also will issue 152 roadside vending licenses for 76 assigned locations.

In addition to these numerical limits, the new rules:

Ban the sale of most clothing items, most kinds of toys, luggage and household appliances. Vendors will be limited to selling "ready-to-eat food," produce, art objects, printed media, specified novelties, beauty products and certain types of general merchandise including umbrellas and sunglasses.

Require every nonfood vendor to have a wooden cart made of pressure-treated lumber, with wheels, and with limitations on size and color scheme. The union estimated that the required carts would cost $1,300 each, and present storage problems.

Limit vending to 5 a.m. to 10 p.m. Sunday through Thursday, and 5 a.m. to 1 a.m. Friday and Saturday.

Increase nonfood vendor license fees from $25 to $106 a year, and to $130 for food vendors, and increase bonding fees from the current $100 to $500 for D.C. residents and $1,500 for nonresidents.

William K. Hunt, president of the 5,000-member local union based in Northeast, said the lawsuit argues that limits on vendors' movements and on sales of certain goods is an illegal restraint of trade. A hearing on the union's motion for a preliminary restraining order is expected to be held within two weeks, union and city officials said.

"The character of street vending has made us urban nomads," said Luqman El-Shabazz. "If they make us stationary, it's an extreme hardship. Let's say one day is payday at an office. Then you go there. If we are restricted to just one spot, we will be out of business very shortly."

Board of Trade spokeswoman Susan Pepper said it is "ludicrous to suggest the Board of Trade had any undue influence" in drafting the rules. She said the board had sought even stricter rules, such as banning all vending downtown, and elsewhere limiting goods even further