An office of the Environmental Protection Agency has had all reference to science removed from its mission statement.

The EPA once proudly told visitors that a large part of its work was scientific research to help improve the climate and the environment. But those references have since been removed and replaced with a reference to things that are "economically and technologically achievable".

Campaigners have said that the change is likely hugely significant, in line with other attempts to remove scientific and climate change work from the US government. It is just one of a range of changes and statements from officials that seem to signal a significant change in the way the government works.

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The removal of the word "is probably the most important thing we've found so far", said Gretchen Gehrke, who works on a team at the Environmental Data and Governance Initiative. "The language changes here are not nuanced—they have really important regulatory implications," she told the New Republic.

The changes were made to the website of the Office of Science and Technology, which among other work develops clean water standards for states.

Until the end of January, the website described that work as "science-based", meaning that it would make recommendations based on peer-reviewed, solid scientific work into what counts as safe levels of pollutant in water meant for drinking, swimming or fishing. But now that reference has been removed, and it has been replaced by a message saying only that clean water will be recommended where it can conform to "economically and technologically achievable standards".

As such, it could mark a major movement from working with scientists to guarantee safe water for citizens of the US. Instead, those decisions could just be made based on the technology that is available.

Even more, the wording could be used to reduce the regulations that currently apply.

Environmentalists often argue that clean water should be assessed by scientists on a performance basis, who check for the amount of certain pollutants that are found in water. But instead, the technological approach could just require companies to install certain pieces of equipment – whether or not that equipment makes the water clean enough to drink or swim in.

The move towards technological language is in keeping with the outlook of new head of the EPA, Scott Pruitt. He has argued repeatedly that his job is to work with stakeholders including industry, farmers and business owners – but not environmentalists or scientists – to protect the environment.