The text includes an aim to “achieve net-zero greenhouse gas emissions for a fair and just transition for frontline communities and displaced workers,” among other high-level ambitions. It also opens the door to using still-unproven technology to eliminate carbon pollution from fossil fuel use — an avenue that many climate activists dismiss as an expensive dead end. But it does not explicitly call for eliminating fossil fuels themselves.

Ocasio-Cortez’s office said the plan’s goal is still to act quickly on climate change with a range of technologies, though allowing fossil fuels to persist is “not what we’re shooting for,” spokesperson Corbin Trent said.

“It’s had lots of different iterations. The goal is to be a zero-carbon economy in 10 years,” Trent told POLITICO when asked whether the resolution calls for banning fossil fuels. “The door is open for technology to solve this problem, sure.”

A U.S. economy that produces a net zero of greenhouse gas emissions would still pose a huge challenge, requiring changes well beyond what former President Barack Obama proposed in his climate regulations.

The soon-to-come legislation is the first concrete step by lawmakers to put language behind the Green New Deal, a largely still-undefined platform of environmental and social-justice goals that has quickly become part of the lexicon of the Democrats’ presidential hopefuls.

Ocasio-Cortez’s campaign platform had previously called for achieving “100% of national power generation from renewable sources” and “decarbonizing” other industries by 2030. The proposed legislative text doesn’t rule out such an ambitious goal, but it could ease the friction between two key elements of the Democratic base: labor groups that support oil, gas and coal projects and environmental groups that oppose them.

The phrasing could also leave more room for a slate of Democratic presidential hopefuls to craft a Green New Deal in their own terms in what is becoming a litmus test for the packed field of contenders. Several 2020 candidates, including Sens. Kirsten Gillibrand (D-N.Y.), Kamala Harris (D-Calif.), Elizabeth Warren (D-Mass.) and Cory Booker (D-N.J.), have endorsed the concept of a Green New Deal, but have not clearly outlined exactly what they mean.

The choices the lawmakers are making after consultation with a broad set of people in a budding coalition of labor, environmental and social and economic justice groups lay bare the challenges of keeping diverse interests fully satisfied.

Omitting a commitment to cease fossil fuel extraction served as a prime example.

“There’s some real questions as to why there wasn’t a ban called for,” said Vijay Das, senior campaign strategist with progressive policy group Demos, who has seen a version of the five-page resolution but cautioned it could change before its release.

Supporters have previously described the Green New Deal as an effort to marshal billions of dollars in public spending to make the U.S. economy carbon neutral while addressing racial and economic justice and providing good-paying union jobs.

The resolution is expected as House Democrats begin a series of hearings this week that will start laying the groundwork for how the caucus plans to address climate change and after President Donald Trump delivers a State of the Union address that will probably touch on his administration’s efforts to remove roadblocks for oil, gas and coal development.

“It names the problem,” Das said of the forthcoming proposal. “It sort of sets ambitious goals as a resolution, but it’s left for the parties to fill in the gaps and the experts to come.”

Ocasio-Cortez has circulated a “Dear Colleague” letter to generate interest and support, according to Axios and Bloomberg. Markey and Ocasio-Cortez’s offices did not respond to requests for comment. Markey’s office did not respond to requests for comment.

The omission of any target date for eliminating fossil fuels frustrated environmental activists and progressives who argue that continued energy extraction will expose people to pollution and health hazards, problems that disproportionately affect communities of color.

“The language I read was clean, renewable, zero emissions — which is that ‘keep the door open’ approach,” said Julian NoiseCat, policy director with the climate group 350.org, adding that his organization pressed Ocasio-Cortez to include a statement requiring the phase-out of fossil fuels.

Some labor unions are skeptical of the Green New Deal, given the likelihood of significant change for their members. Sean McGarvey, president of the North America’s Building Trades Union, said his members who work in the oil and natural gas industry can make a middle-class living, whereas renewable energy firms have been less generous.

“They’re talking about everything except the workers that are doing the work,” McGarvey said at a Monday event with the American Petroleum Institute. API President Mike Sommers said at the event that one-third of construction jobs are in the oil-and-gas sector.

McGarvey said “there has been lately some outreach” from “some of the principals that are putting the plan together,” which he viewed as positive. He told POLITICO that he understood his staff had been in contact with Markey’s office.

Environmental activists within the Green New Deal coalition have acknowledged they need to make stronger inroads with labor in particular. The AFL-CIO and three other labor unions were involved in conversations with Markey and Ocasio-Cortez’s staff, NoiseCat said.

“It was an inclusive drafting process that included stakeholders from environmental, labor and more traditional environmental organizations,” NoiseCat said. “I think that is itself pretty laudable.”

Framing the resolution in terms of “clean” rather than solely “renewable” energy is viewed as an olive branch to labor organizations that rely on a wide sweep of energy industry jobs, such as working on and building natural gas pipelines, nuclear energy and technology that captures and stores greenhouse gas emissions. That comes despite 626 groups last month signing a letter opposing such fuels.

“There’s going to be a 50, 60, 75 year transition — it’s not going to happen overnight even if people want it to happen overnight,” McGarvey said. “But I think getting more specifics in the plan and what it is and how it is and what the timetable is like and then most important for us is what are the economics going to look like in these new emerging industries when it comes to workers.”