At a Glance

Pruitt has rolled back numerous Obama-era environmental policies.Early in his tenure, Pruitt came under fire forsaying CO2 emissions from human activity arenot the primary cause of climate change.

Environmental Protection Agency chief Scott Pruitt may be gone after a controversial and scandal-ridden tenure, but he leaves behind a multitude of changes to environmental policy.

President Donald Trump announced Pruitt's resignationThursday in the wake of more than a dozen federal and congressional investigations into allegations of ethical lapses that included lavish spending, a sweetheart condo lease and using the office for personal gain.

Pruitt, a supporter of oil during his term as Oklahoma's attorney general, was always a controversial choice to head the EPA.

Early in his tenure as EPA chief, Pruitt came under fire forsaying carbon dioxide emissions from human activity are.

Since then, Pruitt has rolled back numerous Obama-era environmental policies.

Overall, the Trump administration has its sights on at least 45 environmental rules, according to a by Harvard Law School's energy and environment program. Theses include25 that are under review at the EPA,the Associated Press reports.

While many critics have praised the embattled EPA chief's departure, many experts note that nothing will change in terms of environmental policy with the naming ofAndrew Wheeler as interim chief.

As Wheeler, aformer coal lobbyist, takes the reigns until a permanent administrator is confirmed by Congress, here are a fewof the environmental legacies Pruitt leaves behind:

Clean Air

Since assuming the nation's environmental helm, Pruitt has overturned six clean air rules and has begun the process to rollback another 12.

These include overturning a from retrofitting new tractor-trailer bodies with old diesel enginesbuilt before tougher pollution standards..

Pruitt has also taken on Obama's signatureClean Power Plan, which was designed to reduce smog, particulate matter, mercury and other dangerous air pollutants. The plan called for a 32 percent reduction of CO2 levelsby 2030 by switching from coal to natural gas.

In October 2017, the EPA announced plans to , saying the rule “exceeds the agency’s statutory authority.”

Clean Water

Under Pruitt, the EPA overturned three clean water rules and begun rollback on another three.

Although a new rule has yet to be written, Pruitt announced plans to change theso-called Waters of the United States rule that dictates how farmers, ranchers and business owners are expected to protect waterways that flow through their property.

Wildlife

Pruitt has overseen the rollback of eight rules that impact wildlife, including the reversal of a from endangered species.

The agency is also looking at changingthe 2018 farm bill that would allow the EPA to approve pesticides without conducting reviews that are now required to protect endangered species.

Attack on Science

Despite an overwhelming consensus among scientists that global warming is a result of human activity, Pruitt important climate data on the agency's website.

Emails obtained under the Freedom of Information Act also revealed discussions among staff to take immediate measures to redirect pertinentURLs, per Pruitt's order.

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Among the buried website pages are the EPA's Student Guide to Global Climate Change and other material for children that were prominently featured under the Obama administration.

In addition, many science pages are no longer being updated, the emails revealed.

Pruitt alsoincreased industrial and business representation on panels that advise the EPA.