A common pesticide used on citrus fruits, almonds and other crops would be banned under a proposal announced Friday by the Environmental Protection Agency.

The proposal would prohibit use of chlorpyrifos, a widely used insecticide that is sprayed on a variety of crops including oranges, apples, cherries, grapes, broccoli and asparagus.

The pesticide, in use since 1965, has sickened dozens of farmworkers in recent years. Traces have been found in waterways, threatening fish, and regulators say overuse could make targeted insects immune to the pesticide.

U.S. farms use more than 6 million pounds of the chemical each year - about 25 percent of it in California.

The EPA said it will take public comments on the proposal for at least two months, with a final rule expected in December 2016. The rule would not take effect until 2017 at the earliest.

The EPA said in a written statement that its current analysis does not suggest risks from exposure to chlorpyrifos in food. But when those exposures are combined with estimated exposure from drinking water in certain watersheds, "EPA cannot conclude that the risk from aggregate exposure meets the Federal Food, Drug and Cosmetic Act safety standard," the statement said.

The EPA banned home use of chlorpyrifos in 2000 and placed "no-spray" buffer zones around sensitive sites, such as schools, in 2012.

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But environmental and public health groups say those proposals don't go far enough.

The Natural Resources Defense Council and other groups filed a federal lawsuit seeking a national ban on chlorpyrifos. The advocacy groups say the pesticide interferes with brain development of fetuses, infants and children.

California's agricultural industry has pushed back against state restrictions, arguing that misuse of the pesticide by some groups should not lead to widespread limits.

Joel Nelson, president of the California Citrus Mutual, a trade association that represents citrus producers, said regulators in his state want to apply a "broad-brush approach" that he called unfair. Alternative pesticides exist, but Nelson said they're not as effective and are more expensive.

Veena Singla, a scientist with NRDC's health and environment program, said farm workers and rural communities "continue to be in harm's way" from the millions of pounds of chlorpyrifos applied to agricultural fields in California and other states.

The EPA's announcement "is a huge step in the right direction, but we think there's enough evidence to ban all its uses now," Singla said.

CropLife America, a trade group that represents pesticide producers, called the proposed ban a "drastic and unnecessary step that is caused by wasteful, agenda-driven litigation" filed by environmental groups.

"We are confident that due legal and scientific process will make this proposed action unnecessary," said Jay Vroom, the group's president.