June 5 (Reuters) - Environmental groups filed notice on Wednesday to sue Canadian oil producer Suncor Energy under the U.S. Clean Air Act for repeated air pollution violations at its Commerce City, Colorado, refinery.

The organizations, represented by environmental law non-profit Earthjustice, said they will bring a civil suit against Calgary-based Suncor over more than 1,000 emission violations that Earthjustice said Suncor reported to the state of Colorado between January 2019 and December 2023.

Under the Clean Air Act, members of the public must give 60 days' notice to the entity they intend to sue before filing a lawsuit.

Commerce City near Denver has Colorado's only refinery, processing 98,000 barrels of oil per day.

The facility has been dogged by problems in recent years including a fire in December 2022 and complaints from residents about air-quality issues.

"If someone was given 1,000 speeding tickets, we'd take away their license," said Margaret Kran-Annexstein, director of Colorado Sierra Club, one of the groups that intends to sue Suncor.

Suncor has said it is implementing improvements to address the refinery's emissions as part of a 2020 settlement with Colorado's public health and environment department.

Ian Coghill, a senior attorney with Earthjustice, said the groups are seeking civil penalties from Suncor and to deter the refinery from further air pollution violations.

"The state has taken action against Suncor but it doesn't seem to have changed anything," Coghill said. "What we're looking for is to hold Suncor accountable and (find) meaningful deterrents to bring Suncor into compliance."

Coghill said the maximum penalty for every day of violation under the Clean Air Act is up to $121,000 and the suit is alleging 9,000 days of violations.

In February the state of Colorado fined Suncor $10.5 million for violating air pollution laws between 2019 and 2021. (Reporting by Nia Williams in British Columbia; Editing by Rod Nickel)