Its been more than a century since the first oil and gas well was drilled in Pennsylvania. 

The first well was successful drilled near Titusville in Venango County in 1859.

According to the Pennsylvania Department of Environmental Protection, this well was the first commercially successful well drilled in the world for oil and gas production. 

Since then, more than 350,000 oil and gas wells have been drilled in Pennsylvania. 

In 2004, the oil and gas industry took a turn in a different direction. 

Range Resources, a company based out of Texas successfully drilled the first vertical well into the Marcellus Shale.

Since then, a number of operating companies have also decided to drill into the shale formation. 

Seneca Resources Corporation is an oil and gas company that has been around for nearly a century.

They will celebrate the company's 100 years in March. 

Seneca Resources has been actively drilling into the Marcellus Shale for a few years. 

They own the mineral rights for approximately 194,000 acres in the Allegheny National Forest. 

The company is the largest rights holder by percentage.

During the month of November, Seneca Resources gave 6 News a look at what goes on at a drilling site. 

Company leaders said there has been a lot of misconceptions surrounding the industry in recent years. 

"People have this perception that this is somehow done in the quiet of darkness without a lot of forethought and practice, but we have professionals on staff, we have professionals that we contract all in the effort to be environmentally responsible," said Rob Boulware, manager of stakeholder relations at Seneca Resources. 

Despite the protests and the opposition many have about the industry, workers said they are keeping the environment safe. 

"We take care of the environment, make sure everything goes as directed. I understand that they don’t understand what we’re actually doing here and the safety steps we go through for preventing environmental instances," said well site foreman, Jud Payne. 

Currently, Seneca Resources is drilling a Marcellus well in Elk County. 

Despite what some people say about the industry, the Environmental Protection Agency is continuously keeping a close eye on production. 

In 2011 there were 10,099 inspections on 3800 wells. The EPA issued 1,159 violations and 191 enforcement actions were taken. 

At the heart of the debate is what is done after drilling, hydraulic fracturing. Many refer to the process as "fracking."

During that process solid steel casing is placed underground and is surrounded by multiple layers of cement.

Environmental groups believe companies are contaminating water. 

Boulware said that is false, and that the company is protecting the fresh water source. 

"You have multiple layers of pipe with multiple layers of cement and you're putting those basic layers through the water acquifer to a level that is several feet below," Boulware said. 

If drilling companies disrupt the water quality or flow in water wells during the drilling process, the law requires them to replace or restore water supplies effected by drilling. The Department of Environmental Protection said the probability of this happening is rare. 

"We are doing whatever we can to not only protect the area that we're drilling, but the public at large," Boulware said. 

While the pipes go deep underground, mud loggers like Travis Bonds track how far the pipes are beneath the earths surface. 

"What we do here is collect samples. Every 30 feet, 60 feet or 90 feet depending on the situation. We analyze the samples to see what they are. To see if we're between a limestone, a shale or sandstone," Bonds said. 

Bonds also has one of the most important jobs. He steers drillers away from potential hazardous conditions. 

"We also monitor gas, we make sure were not getting above or beyond danger zones," he said. 

According to the Department of Environmental Protection, constructing a Marcellus Shale well involves extensive disruption of the earth. Operating companies like Seneca Resources said, it's not much different than what they've been doing for almost a century. 

"The depth of the well has changed but the techniques have certainly while we adopt and bring in new technology the basic technology of drilling is still the same," said Boulware. 

According to the 2012 U.S. Energy Information Agency Report, the Marcellus Shale layer contains 141 trillion cubic feet of recoverable natural gas. Company leaders at Seneca Resources believe this is a resource that will last for decades to come.