In the final weeks and months of the Obama administration, the Environmental Protection Agency’s Office of Pesticide Programs issued a flurry of reports on some of the country’s most widely used pesticides. Decisions made on the basis of these environmental and health assessments will likely determine the level of pesticide residue allowed on the food we eat. They will affect children’s neurological health and development, particularly in agricultural communities. They will determine how farmworkers are protected from pesticide exposures. And they will affect the fate of threatened and endangered species across the country.

So, the stakes are high.

While scores of different pesticides—herbicides, insecticides, and fungicides—are used on U.S. food crops, the five the EPA is now reviewing are the ones to watch: atrazine, chlorpyrifos, glyphosate, malathion, and the insecticides known as neonicotinoids.

Between them, these pesticides are used throughout the United States. All but malathion and two of the five neonicotinoids now under review are used in every one of the lower 48 states. All have environmental and health effects that raise serious concerns—enough so that some are banned or severely restricted in the European Union. These pesticides are also all used on some of the most commonly eaten and popular produce, including apples, cucumbers, grapes, kale, spinach, strawberries, and tomatoes, all of which appear on the Environmental Working Group’s (EWG) 2016 “Dirty Dozen” list.

Below we recap the state of play for each of these five pesticides.

Atrazine

Where it’s used: Atrazine, considered the second most widely used pesticide in the U.S., is applied mostly to corn in the Midwest and sugarcane in the South.

Health and environmental impacts: It has been linked to adverse developmental, hormonal, and reproductive effects, and potentially to certain cancers. Atrazine easily runs off fields, contaminates groundwater, surface and rain water, and is one of the pesticides most frequently detected in U.S. Geological Survey (USGS) monitoring. “There’s a lot of atrazine in the drinking water in the Midwest,” explained EWG senior analyst Sonya Lunder.

Legal/regulatory status: The EPA is now in the process of reregistering—or reapproving—atrazine’s use. In June 2016, the agency released a draft ecological risk assessment that concluded heavy atrazine use can pose chronic risks to birds, mammals, fish, amphibians, and aquatic invertebrates (the insects and shellfish that form the base of the food web). It also found that the herbicide is adversely impacting a wide array of plants it’s not supposed to be harming. Or, as the Center for Biological Diversity (CBD) summed it up, the “atrazine that’s released into the environment in the United States is likely harming most species of plants and animals.”

The EPA is also now evaluating atrazine’s—and also glyphosate’s—impacts on endangered species, an action that follows a legal settlement with CBD.

What’s next: The EPA’s Scientific Advisory board is due to review the draft ecological risk assessment sometime this year, with any new atrazine restrictions to follow. This decision, Lunder said, will be “incredibly-high profile, as it will affect a lot of people.”

Chlorpyrifos

Where it’s used: Chlorpyrifos is used on corn and many fruit and vegetable crops, as well as in nurseries and greenhouses all across the country. Consequently, it has been found widely in surface water.

Health and environmental impacts: Chlorpyrifos belongs to the category of insecticides called organophosphates, which kill insects by attacking their nervous systems. But due to concerns about its neurotoxicity, especially to children for whom exposure can cause potentially irreversible changes in the brain, the EPA has been gradually restricting its use.

However, levels of chlorpyrifos residue measured on produce regularly eaten by women and children were found by the EPA to exceed current safety levels by “up to 14,000 percent,” said Natural Resources Defense Council (NRDC) scientists Miriam Rotkin-Ellman and Veena Singla. Current research also shows “that children’s health effects are happening at lower levels than adult exposure,” added NRDC senior scientist Jennifer Sass.

Legal/regulatory status: Chlorpyrifos is no longer allowed by homeowners, or on farms growing tomatoes—and use on apples, citrus, and nut trees has been curtailed. In October 2015, due to ongoing concerns about its neurotoxicity, the EPA proposed eliminating chlorpyrifos use on all food crops—and gathered public comment on the proposal.

What’s next: The EPA is due to finalize this decision by March 31, 2017—a court-ordered deadline resulting from litigation by NRDC and Pesticide Action Network North America (PANNA). But especially with new leadership on the way at the agency, PANNA’s organizing director and policy advocate Paul Towers says he’s “concerned that EPA won’t actually follow the science and actually ban it.”

Glyphosate

Where it’s used: Glyphosate (AKA Roundup) is considered the most widely used pesticide in the U.S. and around the world. Nearly all the corn and soy grown in the U.S. is now treated with glyphosate. It’s also used on wheat, rice, and a variety of fruits and vegetables. Use has approximately doubled in the past 10 years, due largely to corn and soy genetically engineered to resist glyphosate.

Health and environmental impacts: In 2015, the World Health Organization’s International Agency for Research on Cancer (IARC) classified glyphosate as a probable human carcinogen. Glyphosate has also been linked to hormone disruption, antibiotics resistance, and other adverse health effects, and it has been found in water sources across the U.S. Given glyphosate’s importance to the agricultural chemical industry, discussion of the herbicide’s health effects has become controversial, even contentious.

Legal/regulatory status: The EPA is now in the process of re-approving glyphosate’s use and assessing its potential to cause cancer. In September 2016, the EPA released a report that—unlike IARC—concluded glyphosate was unlikely to be a human carcinogen.

Adding to the debate, California has proposed adding glyphosate to the list of chemicals the state considers carcinogenic—a move that would require cancer warning labels on all glyphosate products. Monsanto, the world’s leading glyphosate producer, sued to stop this, but a California court has ruled the state can proceed.

What’s next: An EPA Scientific Advisory Panel met in December to review this report. The EPA’s draft assessment of glyphosate, which will include that panel’s conclusion and precedes any new use restrictions, is due out in the third quarter of 2017.

Malathion

Where it’s used: Malathion is used on a wide variety of food crops—and livestock feed—most intensively in California’s Central Valley, Florida, parts of Kansas, and the Pacific Northwest. It’s also used to control mosquitos, such as in the recent efforts to curtail the spread of the zika virus.

Health and environmental impacts: Like chlorpyrifos, malathion is an organophosphate and neurotoxin. Malathion can be absorbed by the skin as well as inhaled and can adversely affect the digestive, respiratory, nervous, and cardiovascular systems. Malathion has been found in surface water and can also move with air and fog.

Legal/regulatory status: In September 2016, as part of its malathion reregistration process, the EPA released its draft human health assessment of the pesticide. The agency noted that there’s some evidence to suggest its carcinogenicity, but whether this affects people is not yet known. However, it also added that the current protections required for agricultural workers may be inadequate.

In comments submitted to the EPA, agricultural trade associations, including CropLife America, Responsible Industry for a Sound Environment, and the California Fresh Fruit Association said the EPA’s assessment is too “conservative” or protective. But PANNA’s Towers strongly disagrees. “We’ve actually advocated for the phase-out of all organophosphates,” he told Civil Eats.

What’s next: The EPA’s “draft interim” proposal for future malathion use is due out in the third quarter of 2017.

Neonicotinoids

Where they’re used: First approved for use in the U.S. in the 1990s, neonicotinoids are now considered the world’s most widely used and fastest growing type of pesticide. Use on U.S. corn and soy has increased ten-fold on the past decade. “Neocics” are also used on wheat, grapes, citrus, and nut orchards, and applied as sprays and seed treatments. The use of some neonicotinoids has doubled or tripled in less than 10 years.

Health and environmental impacts: Neonics have been implicated in bee die-offs across the country, and while they’re not considered the sole cause of the ongoing decline in pollinators, they are understood to be a significant contributing factor. Their human health impacts have also just begun to be investigated. Researchers have also linked neonicotinoids to declines of numerous bird species.

These are systemic pesticides, meaning that they stay with the plant as it grows and are present in pollen and other plant parts. USGS has found neonicotinoids in streams across the country, suggesting that they are moving through the environment. Dust from the pesticide seed coatings is also allowing neonicotinoids to spread in problematic ways.

Legal/regulatory status: The EPA is now reviewing the toxicity of five different neonics. Starting this month, the EPA was due to begin releasing ecological and human health assessments for the same five, but none of the reports have been released. Meanwhile, to protect pollinators, various states including Maryland, Minnesota, and Oregon have restricted neonicotinoid use.

What Will 2017 Bring?

It’s not yet clear how the new administration’s rapid, large-scale promises to curtail regulations will affect these and other pesticides but it’s likely they will. When Civil Eats asked the EPA press office on January 30 about the reviews of these five important pesticides the agency provided the following, brief response: “At this time EPA has not made any changes to these chemicals’ schedules.”

However, President Trump’s recent executive order instructing agencies to repeal two regulations for every new one enacted could affect pesticide rules, said University of Texas School of Law professor Thomas McGarity. When the EPA set pesticide “tolerances” or residue levels, those are rules that could fall victim to the order, he explained.

However, these are big-ticket items when it comes to affecting food, drinking water, and environmental health, and advocates are already working to keep the spotlight on policies that will impact these and other pesticides.

“These are preventable exposures, contributors of preventable and long-term harm,” said NRDC’s Sass. “These are things we can do something about because we regulate pesticides,” she says. And she acknowledges, “There are [also] things we [as individuals] can do, including buying as much pesticide-free as you can.”