The core mission of the Environmental Protection Agency, or EPA, "is to protect human health and the environment." As part of that mission, the agency works to ensure that "national efforts to reduce environmental risk are based on the best available scientific information."

President Donald Trump, EPA Administrator Scott Pruitt, and their allies in Congress have proven themselves hostile to the role of science in achieving the agency’s mission but all too willing to heed the requests of polluters.

Here are the top seven ways in which science is under siege at the EPA.

1. Administrator Pruitt rejected decades of science to keep a dangerous pesticide on the market

Chlorpyrifos is a common agricultural pesticide that causes neurological harm in children who were exposed to it in utero. In 2016, the EPA’s scientists concluded that the agency should ban chlorpyrifos after finding unsafe levels of the chemical on apples, peaches, oranges, and other fruits. Dow Chemical, one of the largest makers of chlorpyrifos-based products that has actively fought EPA limits on the chemical’s use, gave $1 million to President Trump’s inauguration committee and leads a presidential advisory committee on manufacturing. On March 28, Pruitt rejected the findings of the EPA’s scientists; denied a petition to ban the chemical; and delayed further action until 2022, when the EPA is required to re-evaluate its safety again.

2. The EPA is full of climate science deniers, starting at the top

Despite the overwhelming scientific consensus to the contrary, EPA Administrator Pruitt has questioned whether carbon dioxide causes climate change and the magnitude of humans’ role in driving it. Pruitt also has staffed the EPA with a litany of climate change science deniers, drawing particularly heavily from the office of Sen. Jim Inhofe (R-OK)—who famously threw a snowball on the Senate floor to prove that climate change is a hoax—to fill senior leadership positions. The EPA transition and beachhead teams, which helped shape the EPA’s early agenda under the Trump administration, also featuredseveral climate change deniers, including Steven Milloy, who refers to the EPA’s finding that greenhouse gases endanger human health and the environment as “the original climate sin.”

3. President Trump determined that climate change has no cost

On March 28, President Trump signed an executive order nullifying much of former President Barack Obama’s Climate Action Plan. As part of that order, Trump directedfederal agencies to stop using the social cost of carbon—the estimated economic cost of emitting 1 ton of carbon pollution into the atmosphere—in their cost-benefit analyses. The effect of this wonky change will be significant. If the EPA assumes that 1 ton of carbon pollution has no cost, then the agency will be unable to quantify the benefits of cutting carbon pollution. This will make it easier for Administrator Pruitt to defend weakening or nullifying the Clean Power Plan and other climate policies.

4. President Trump has proposed drastic funding cuts to the EPA’s scientific research

President Trump’s so-called skinny budget calls for large budget cuts at the EPA, including a 31 percent reduction agencywide that will slash staff by 25 percent and eliminate 56 programs. Many science programs are on the chopping block. The proposal would halve the budget for the EPA Office of Research and Development, “whose leading-edge research helps provide the solid underpinning of science and technology for the Agency.” Funding for the EPA’s Science to Achieve Results grants could disappear, eliminating critical funding for academic research on water quality, air pollution, and other priorities. According to Science, former EPA Administrator Gina McCarthy warns that President Trump is “not just going after the climate science in the agency, but going after the scientists … that do fundamental air and water and land work.”

5. President Trump and Congress want to slash the EPA’s scientific expertise

Congress created the EPA Science Advisory Board, or SAB, in 1978 to “review the quality and relevance of the scientific and technical information being used by the EPA or proposed as the basis for Agency regulations.” The SAB receives significant cuts in the proposed budget: 84 percent from its operating budget and 14 percent from support staff resources. The board may only be able to conduct two peer reviews each year instead of 20.

Congress is attacking the SAB as well. The EPA Science Advisory Board Reform Act, which passed the House in March, could prevent the nation’s top scientists from participating in the SAB if, paradoxically, they would be advising the SAB on matters related to their own expertise. The bill also could disqualify scientists who have received EPA grants while making it easier for industry stakeholders to participate in the process. The result would be to threaten the SAB’s ability to provide sound, unbiased scientific advice to the EPA administrator—which is probably the end the bill is designed to achieve.

6. Rep. Lamar Smith wants to block the EPA from using sound science to set pollution standards

Rep. Lamar Smith (R-TX), an ardent climate denier who has been leading the congressional attack on science, introduced the Honest and Open New EPA Science Treatment Act, or HONEST Act. It passed the House in March. The HONEST Act would prevent the EPA from issuing rules based on scientific data or models that are not publicly available. The problem is that many data cannot be publicly released because they contain personal health records or trade secrets. As such, the bill could block the EPA from using the best available scientific evidence to set pollution limits or develop ambient air quality standards. This is not the result of poorly drafted legislative text—it is intentional. Rep. Smith has a long history of attacking science as a means of making it more difficult for the EPA to hold polluters accountable.

7. President Trump has failed to hire scientists throughout the government

President Trump has kept many critical science positions vacant since he took office in January. Days after inauguration, Trump issued a hiring freeze for the federal government, leaving more than 350 positions at the EPA empty, including more than 100 key science jobs. To date, he has not appointed a chief science adviser or staffed the White House Office of Science and Technology Policy. John Holdren, former science adviser to President Obama, says “it would be unwise in the extreme for the president to let the current vacuum in science advice in the White House persist,” since “[i]nsights from science and technology are relevant to many of the decisions about actions and policies that a president must make.”

These seven attacks—which, sadly, are unlikely to be the last—are part of a coordinated and deliberate agenda. President Trump, Administrator Pruitt, and their allies in Congress want to obscure the science that clearly demonstrates the need to cut air and water pollution by the powerful corporate interests that offer them the greatest political support. Without hard science in the way, they can more easily spin the story they want to sell—that corporations can pollute unabated without hurting our lungs, waterways, and climate.