Internal government records obtained by the Guardian raise questions about the role of Pennsylvania governor Tom Wolf in permitting construction of a controversial fossil fuel pipeline that now faces two criminal investigations stemming from widespread environmental and property damage.

The 350-mile, $2.5bn Mariner East 2 natural gas liquids pipeline through southern Pennsylvania has sparked growing outrage. It has caused roughly 140 documented industrial waste spills into wetlands and waterways, destroying numerous residential water wells, and opening large sinkholes just steps from residents’ homes.

It is being constructed by the Texas-based Energy Transfer Partners (ETP), which first gained notoriety as the builder of the Dakota Access pipeline, a project that drew international attention and widespread opposition, particularly from Native Americans, in 2016 and 2017 on the northern Great Plains.

Emails, text messages and regulatory records show that the secretary of Pennsylvania’s department of environmental protection (DEP), Patrick McDonnell, directed staff to cut short their environmental review even as numerous shortcomings remained in the project’s permit application. The department also appeared to be under pressure from Wolf’s office at the time.

DEP staff internally circulated two “deficiency letters” on 20 January 2017 that they were preparing to send to an ETP subsidiary, Sunoco Logistics, citing inadequacies in the company’s plans concerning earth disturbance activities and drilling beneath water bodies.

Five days later, a senior official in Wolf’s office, Yesenia Bane, texted McDonnell to request the agency refrain from sending a deficiency letter, pending a meeting involving Wolf, the governor’s chief of staff, and McDonnell.

“Understood,” McDonnell wrote in response. Less than an hour later, McDonnell emailed several staff members involved in the pipeline review that “Govs [sic] office needs a list of the outstanding issues ASAP”.

Roughly two weeks after that, the DEP approved the pipeline without requiring many of the environmental safeguards it had initially sought. A DEP senior official who was involved in the Mariner East 2 project, John Stefanko, noted in a later legal deposition that McDonnell had directed staff “that we needed to make a decision by February 10th”, although the review had been scheduled to persist for at least several additional months.

The text messages and a handwritten note from a DEP staff member show that the then CEO of Sunoco, Mike Hennigan, regularly talked to McDonnell in the lead-up to the permit authorization, and that McDonnell reported to the governor’s staff on those conversations. “If I need to talk to Mike five times a day, that’s what we will do,” McDonnell wrote to Bane.

A previous report on the text messages involving McDonnell and Bane helped spawn an ongoing Pennsylvania Ethics Commission investigation of Wolf’s office. The other records reviewed by the Guardian have not previously been reported.

JJ Abbott, a spokesperson for Wolf’s office, said the governor never directed the DEP to accelerate its approval of environmental permits.

“Decisions around the permits and any conditions were made by DEP,” Abbott stated in an email. “The governor’s staff routinely schedules briefings on issues of public interest and asks for updates on those issues from agencies. This is normal and responsible governing.”

A previous public statement by Wolf, however, indicates he went beyond just seeking updates. “I asked them what their timetable was and then, ‘Let’s do it,’” he told CBS Pittsburgh in February 2017. “As a CEO, I was the same way. You say you’re going to do something, let’s get it done.” He added: “That’s not political pressure, that’s actually trying to manage an organization.”

A DEP spokesperson also defended the permitting, saying in a statement: “The permits that were issued contain the most environmentally protective conditions of any permits in the department’s history.”

But Alex Bomstein, an attorney for the Philadelphia-based environmental protection group the Clean Air Council, said the DEP ultimately failed to make the company account for many geologically sensitive areas, wetlands and residential well locations.

“Cutting a pipeline corridor across Pennsylvania is bound to be environmentally damaging, but the government was willing to overlook a lot of the things that made this project especially risky,” Bomstein said.

A gas pipeline is seen at a farm outside Dimock, Pennsylvania, in 2012. The Mariner East 2 pipeline across southern Pennsylvania was approved in 2017. Photograph: Jim Lo Scalzo/EPA

Wolf, who is a Democrat, has received substantial donations from companies with a financial stake in Mariner East 2, including $20,000 toward his 2018 re-election campaign from the gas producer EQT Corporation, which has a shipping contract with the pipeline. During his 2014 campaign, he received $1.5m in campaign contributions from organizations, individuals and Pacs tied to the oil and gas industry.

Yesenia Bane, Wolf’s deputy chief of staff, who sent the text messages to McDonnell, the DEP secretary, is married to a former oil and gas lobbyist.

Since the project was first approved more than two years ago, the political environment surrounding it has changed.

On 12 March, Pennsylvania’s attorney general, Josh Shapiro, and the district attorney of Delaware county, Pennsylvania, announced a joint criminal investigation of the pipeline and the company. The district attorney of Chester county, Pennsylvania, also launched a criminal investigation in December.

A bipartisan group of 14 state legislators have also signed a letter to Wolf requesting he issue a moratorium on both of the existing Mariner East pipelines until ETP provides an emergency response plan to first responders in Chester county in case of a pipeline rupture or other emergency.

Many of the legislators represent the populous suburbs west of Philadelphia, where the pipeline runs alongside schools, subdivisions, and an elder care facility.

The pipeline is potentially a life or death issue for many residents of the area, said Eric Friedman, spokesman for the group Del-Chesco United for Pipeline Safety, a group of concerned local residents. According to a study cited by authorities in Delaware county, the probable fatality zone of an explosion of the Mariner East 2 pipeline is more than one mile wide.

“Many parents here fear that our children might not come home from school one day,” said Friedman, whose fourth-grade son attends a school near the pipeline route.

After a separate ETP pipeline in Pennsylvania exploded last month, burning down a house, barn and other structures, the DEP placed a moratorium on issuing any new ETP permits in the state – including several not-yet-issued water quality permits and other approvals for Mariner East 2.

The pipeline’s construction has resulted in more than 80 environmental violations. The DEP has assessed more than $13m in penalties against the company. Several times, ETP has been caught drilling beneath waterways where it had no permits from the DEP, on some occasions contaminating residential well supplies.

In late 2017, ETP failed to report a leak of drilling fluid during pipeline construction in in West Whiteland Township which caused sinkholes to open in a residential subdivision. One 20ft-deep chasm, which exposed the Mariner East 1 pipeline, came within 10ft of a house. Even though the company claimed it had remediated the problem, roughly a year later, the pipeline caused sinkholes again in virtually the exact same location, raising fears of a pipeline explosion.

An ETP spokeswoman, Lisa Dellinger, said in a statement to the Guardian that “there is no legitimate basis for conducting a criminal investigation into our company and the Mariner East pipelines”, and also said the company had worked closely with local officials to respond to citizens’ concerns.

But Bomstein said the project’s hasty approval resulted largely from industry pressure.

“It’s important to recall that the company put political pressure on our government, and the government caved to that pressure,” he said.