Washington (CNN) President Donald Trump made a campaign trail promise to eliminate the Environmental Protection Agency -- a department once looked to as an important national force tackling climate change -- and during his first 100 days in office has held true to his word, taking swift strides towards dismantling the agency and rolling back regulations.

Alongside EPA Administrator Scott Pruitt, a former Oklahoma attorney general who once worked tangentially with the fossil fuel industry to oppose Obama-era regulations, the Trump administration has so far issued a flurry of EPA-focused executive orders, proposed employee buyouts, handed down a social media gag order and is proposing significant cuts to the EPA budget.

Pruitt and Trump alike have touted their new agency agenda as a win for economic growth and those who work with businesses in the oil and gas industry have likened the atmosphere to finally having their voices heard.

"We were looking forward to a new admin that was not going to be openly hostile to us," said Kathleen Sgamma, president of the Western Energy Alliance. "So our expectations going in were optimistic thinking at least we have somebody who talks about encouraging oil and natural gas development. What we didn't expect was such a comprehensive understanding of the ways that red tape is being used to stop not just our industry but economic growth and job growth in other industries."

The White House is also highlighting its EPA regulation roll-backs through use of the Congressional Review Act as one of the brightest moments so far. Speaking to reporters Tuesday, White House Legislative Affairs Director Marc Short called the actions the "biggest legislative achievement" of Trump's first 100 days in office, next to the confirmation of Supreme Court Justice Neil Gorsuch.

The GOP Congress used the law to nullify the EPA's Stream Protection Rule, a regulation that in part limited coal mines from dumping waste into streams.

However, the administration still remains in the beginning stages of enacting the changes it wants to see within the agency. Many of Trump's executive orders lack formal backing in policy and there remains a long process ahead to formalize any de-regulations.

Fulfilling his promise from the start

From the start, the White House made efforts to change the EPA's regulatory authority. Through a series of executive orders, some a mere days after Trump took office, the administration made clear its intention to support what it views as economic growth over environmental protections -- a maneuver it routinely calls cutting red tape.

In February, Trump issued an executive order asking the EPA to repeal and replace the Clean Water Rule, also known as the Waters of the US rule.

In March he introduced another sweeping executive order to look into ways to roll back regulations on a number of Obama-era policies pertaining to climate change, that included emissions rules for power plants, limits on methane leaks, a moratorium on federal coal leasing, and the use of the social cost of carbon to guide government actions.

Additionally, the EPA granted a number of industry petitions to reconsider or delay the implementation of EPA rules that were previously passed under Obama, including delaying the implementation of a chemical storage rule that aimed to tighten safety requirements for companies. The regulation was crafted following a 2013 fertilizer plant explosion in Texas that killed 15 people.

In April, Pruitt has told oil and gas industry leaders that the agency will reconsider its methane emissions rule following a petition from industry leaders, a 90-day delay.

"Sometimes you hear politicians who talk about that but you wonder if they will have people in place who understand how to effectively cut through the red tape," said Sgamma. "I did not expect that the Trump administration would be fairly sophisticated in countering that and willing to do so quickly in the first 100 hundred days."

"There is no way to sugarcoat this, President Trump has taken a wrecking ball to environmental protection in the US," said Ken Kimmell, president of the Union for Concerned Scientists. "Frankly I didn't think this would happen with the severity with this is happening. We have had changes in powers before. Different presidents strike a different balance. But this is a severe attack that we didn't expect."

Hiring freeze and job cuts

One of Trump's initial executive orders placed a blanket hiring freeze across government departments and agencies. It left 350 positions at the EPA unfilled including more than 100 scientists in specialties like environmental science, life science, and physical science.

Documents released through a Freedom of Information Act request by the Sierra Club and reviewed by CNN , showed the hiring freeze affected an additional 140 people internally chosen for jobs or, in some cases, offered jobs but could not be finalized.

"That's about one-third of the total number of positions hiring was frozen for, so we are seeing high skilled people being held up from working at the agency," Sierra Club global climate policy director John Coequyt told CNN.

The positions impacted by the government-wide hiring freeze include more than 70 scientists and engineers in areas like the environment, physical science and life science -- and at least six law enforcement officers.

Additionally, the EPA is planning to reduce its workforce through buyouts and an early retirement program, according to an internal memo obtained by CNN . The memo also said the agency plans to continue its hiring freeze, with "very limited exceptions," even as the government-wide freeze expires. The internal memo said the agency hopes to complete the buyout program by the end of the fiscal year.

In a March budget blueprint the Trump administration proposed additional budget cuts that would significantly impact the EPA. Under it, the EPA would lose 3,200 jobs -- in addition to the number already left unfilled and loose more than 30 percent of its budget -- about $2.6 billion. The budget also aims to eliminate funding entirely for the Great Lakes Restoration Initiative, Chesapeake Bay funding, and other regional programs.

Next step: Court

While both environmentalists and oil and gas businesses agree that the administration has so far put in a great deal of effort when it comes to laying out its environmental and energy plans, they also know getting them implemented will be a long -- and likely rocky -- road.

Several sources outlined to CNN three feuding factions within the agency: firm conservatives who want to see a more aggressive pullback of the agency's regulatory footprint; career employees, many of whom are concerned the new administration is hostile to environmental and climate concerns; and Pruitt's inner circle, who are reluctant to go along with some of the most unpopular rollbacks that are controversial even among moderate Republicans.

"Pruitt shares the ideology that excessive EPA overreach and over regulation does need to be rolled back, but he's resistant to some regulatory action for fear some of the more unpopular actions could harm his future political career," said another source close to the administration who is concerned about Pruitt's first month on the job.

Most expect that the arguments over regulations will ultimately end up in court. Groups like the National Resources Defense Council plan to fight back through a range of tools including legal measures, legislative action and public opposition.

"As we expected, the Trump administration has launched an unprecedented set of attacks on a wide range of environmental protections on air, water and land. But in most cases, because he has been constrained by law, he hasn't actually been able to effect much so far," said David Goldston, director of government affairs at NRDC. "We think we will be able to successfully block much of what he's trying to do."

Goldston continued, "Presidents are limited by law and the law requires consistency with science and he is not in a strong position on those."

Industry leaders are equally gearing up for a legislative challenge in hopes to make permanent any of the changes that may occur under the Trump administration.

"If there's one thing everyone learned from the previous admin, if you live by executive fiat you die by executive fiat," said Christopher Guith, senior vice president of the Chamber of Commerce. "So the goal here is to not just get rid of things by the stroke of the pen like Obama created them, it's to do it in a durable way so that the next person in the oval office can't just do away with it."

Clarification: This story has been updated to clarify which regulations have been affected by the Congressional Review Act.