After years of inaction, the U.S. House passed a bill Wednesday directing federal authorities to assess the risks that ocean acidification – a byproduct of global warming – presents to coastal communities, fishermen and the aquaculture industry.

Scientists have shown the oceans are becoming more acidic as they absorb greater quantities of carbon dioxide from the atmosphere. In the Gulf of Maine, researchers have documented that acidic conditions stunt clam growth and make it so difficult for baby oysters to build their first shells that they often die before they can complete them. The effects on lobster, Maine’s most valuable fishery, remain unclear.

Rep. Chellie Pingree, the Democrat representing Maine’s 1st District, first introduced the Coastal Communities Ocean Acidification Act nearly four years ago, but it failed to receive so much as a hearing, despite having bipartisan support. It passed Wednesday morning by a unanimous voice vote, with six Republican co-sponsors and no concerted opposition in the House, where Democrats have been in the majority since late last year.

“I’m so proud to see the House’s unequivocal, unanimous support for my ocean acidification bill today,” Pingree said in a statement immediately after the vote. “It goes to show that it’s not controversial to study the changes happening to our oceans – in order to take action, we have to understand what we’re dealing with.”

Rep. Jared Golden, a Democrat representing Maine’s 2nd District, was a co-sponsor of the bill, as was his Republican predecessor, Bruce Poliquin.

The bill directs the National Oceanic and Atmospheric Administration to work with state and local experts to assess the likely impacts of acidification on coastal communities and identify gaps in knowledge. NOAA would prepare a public report on which communities are most exposed to the problem, and support state efforts to assess their own vulnerabilities.

In early March, Republican Sen. Lisa Murkowski of Alaska reintroduced a companion bill in the U.S. Senate, which is co-sponsored by six senators including both of Maine’s: Republican Susan Collins and independent Angus King, who caucuses with the Democrats. Its prospects are unclear, as Senate Majority Leader Mitch McConnell, a Kentucky Republican, has been focused on confirming as many federal judges as possible at the expense of moving legislation. This prompted Louisiana Republican John Kennedy to complain May 22: “We have done nothing. Zero. Zilch. Nada.”

Murkowski’s spokeswoman, Karina Borger, said Murkowski would look for opportunities to advance the bill. “It’s definitely a priority of hers, and she will advocate for it and push for it,” Borger said.

Meanwhile, the Maine Legislature is expected to vote next week on Gov. Janet Mills’ climate change bill, L.D. 1679, which would establish a state Climate Change Council to oversee Maine’s efforts to lower greenhouse gas emissions and prepare for climate-change-driven disruptions, including ocean acidification and other changes within the Gulf of Maine.

“Compared with what has been going on nationally, we have been very encouraged to see fairly broad bipartisan support for creating a climate plan and figuring out how to make it happen,” said Hannah Pingree, who has overseen the drafting of the bill as head of the governor’s Office of Policy and Management.

The Maine bill is likely to pass, as Democrats control both houses of the Legislature, it received unanimous, bipartisan committee approval and is one of the governor’s priorities.

Carbon dioxide levels in the Earth’s atmosphere are more than 70 percent higher than they were before the Industrial Revolution, and now stand at the highest level in at least 800,000 years. The levels would be worse but for the fact that the oceans absorb some of that additional carbon dioxide, but that has caused them to become 30 percent more acidic over the past century and a half, creating conditions that interfere with the chemical processes by which clams, oysters and other organisms grow their shells.