After fighting for two decades over a highly visible pollution source, oil refiners, air regulators and environmentalists welcomed a historic new rule adopted Wednesday to cut refinery flare pollution.

Meeting in San Francisco, the Bay Area's air quality board approved the rule, requiring five refineries to develop emission-reduction plans for flares.

It is the first rule in the nation to limit flares, which are designed as safety devices to burn off gases during emergency pressure buildups and other unusual events. But for years, community activists have argued that the fiery, smoky flaring events are too easily triggered by refineries looking to cut costs.

``We've debated this for 20 years. The rule is long overdue,'' said Mark Ross, a Martinez city councilman on the Bay Area Air Quality Management District Board. ``Open flares are good for the Olympics, but not for communities.''

The vote to approve was 15-1.

Chris Daly, a San Francisco supervisor, said he supported the rule but voted ``no'' only because he thought the study on rule options was not thorough enough.

Many past public discussions on the flares were rancorous.

In contrast, speakers from different camps Wednesday said the rule was a compromise that will serve as a national model.

``This is the first and only rule of its kind in the country to comprehensively address flares,'' said Greg Karras, senior scientist at Communities for a Better Environment, a statewide group based in Oakland. ``We want a stronger rule, but this air board should be commended for having the courage to adopt this.''

Refinery operators can live with the rule, even if they believe flare pollution estimates have been overblown, said Joe Sparano, president of the Western States Petroleum Association.

``We believe we can safely implement the rule,'' he said.

Karras and other environmentalists said the rule should set strict flare-emission limits for sulfur, a lung irritant.

But air board members said they didn't want to delay the rule adoption, as would happen if they waited for a new study to consider sulfur limits.

Board members said they would consider sulfur limits later.

Jack Broadbent, the air district's chief executive officer, said the rule protects industrial neighbors by requiring each refinery to plan equipment and operational changes to minimize gas sent to flares.

``The idea is to prevent pollution rather than burn it,'' Broadbent said.

The Bay Area refineries are owned by Chevron, Shell, Tesoro, ConocoPhillips and Valero.

The rule will cost the petroleum industry at least $1.4 million and as much as $10.6 million annually per refinery, air district consultants estimated in a study.

Those annual costs amount to a range of between 0.2 percent and 2 percent of the net incomes of the plants, the consultants said.

Refiners have until November 2006 to submit the pollution reduction plans.