WASHINGTON (REUTERS) - The Environmental Protection Agency (EPA) on Wednesday (July 22) announced it was proposing the first US emissions standards for commercial aircraft.

In 2016, the UN International Civil Aviation Organisation (ICAO) agreed on global airplane emissions standards aimed at makers of small and large planes, including Airbus and Boeing, which both backed the standards.

The EPA-proposed regulation seeks to align the United States with the ICAO standards, EPA Administrator Andrew Wheeler said.

"We are implementing the ICAO recommendations, ICAO standards,"Wheeler told reporters.

Reuters, which first reported the proposal earlier on Wednesday, would apply to new type designs as of January 2020 and to in-production planes or those with amended type certificates starting in 2028.

They would not apply to planes currently in use.

Aircraft account for 12 per cent of all US transportation greenhouse gas emissions and 3 per cent of total such US emissions.

They are the largest source of transportation-related greenhouse gas emissions not subject to standards.

Wheeler said it was critical the US adopt the standards, because countries could ban US-assembled planes if they do not meet ICAO standards.

EPA is expected to finalise the rules next spring.

The Federal Aviation Administration will then issue separate rules to enforce the standards.

Some environmentalists argue the ICAO rules and EPA did not go far enough.

Clare Lakewood, climate legal director at the Centre for Biological Diversity, said on Wednesday, "this toothless proposal does nothing to meaningfully address the serious problem of aeroplanes' planet-warming pollution."

She noted EPA was not estimating any emissions reductions as a result of the proposal.

Wheeler said the proposal is based on "where the technology is today... You can't really set the standard that can't be met."

Boeing said the EPA proposal "is a major step forward for protecting the environment and supporting sustainable growth of commercial aviation and the United States economy."

Airlines for America, a trade group, said the rules will help US airlines "achieve carbon neutral growth in the near term and to cut net carbon emissions in half in 2050 relative to 2005 levels."

Under President Barack Obama, the EPA in 2016 declared aircraft emissions posed a public health danger.

In January, environmental groups filed a notice of intent to sue EPA for failing to regulate aircraft emissions.