Bernie Sanders released an anti-fracking campaign advertisement on Monday subtly attacking Hillary Clinton's previous support on the controversial drilling method.

"Do Washington politicians side with polluters over families?" narrator Susan Sarandon says during the 30-second clip. "They sure do, because Big Oil pumps millions into their campaigns. Bernie Sanders is the only candidate for president who opposes fracking everywhere."

Fracking is the process of extracting oil and natural gas by drilling down into the earth. Sand, water and chemicals are injected into rocks below the surface at high pressure, allowing gas to flow up a well. Chemical runoff and escaping gases are what make hydraulic fracturing of rocks risky, potentially contaminating groundwater in surrounding areas.

The ad says these "dangers, cancer-causing chemicals" are being overlooked by Washington politicians choosing to side with Big Oil companies over families.

"If we are going leave this planet in a way that is healthy and habitable for future generations we need bold action now," Sanders said in a press release coinciding with the ad.

Sanders Challenges Clinton Environmental Record

New York banned fracking last summer, but Sanders is hoping his environmental record resonates with New Yorkers voting in next week's Democratic presidential primary.

The Vermont senator is positions himself to Clinton's left on topics ranging from fracking to climate change, and said as much at a rally at Marine Veterans Memorial Arena on Monday, in an area known as the "fracking belt."

"I am very worried about the future of clean water in our country and in fact around the world," Sanders said. "We cannot simply frack and cause massive pollution and this something where Secretary Clinton and I have strong disagreements."

Sanders' press release pointed to "very important differences" between himself and Clinton, specifically his opposition to the Keystone XL pipeline and offshore drilling measures the former New York senator initially supported. The Sanders campaign also notes that lobbyists with ties to Exxon and BP funneled thousands of dollars directly into Clinton's campaign.

Clinton denounced the claims over the last week saying she does not take money from gas industry PACs or corporations, but is open to donations from individuals who work in the industry. Unlike Sanders, Clinton is open to fracking, albeit with tougher restrictions.

New York Latinos Favor Clinton

A Monmouth University poll released Monday gives Clinton a double-digit lead over her grassroots opponent.

While the Democratic contenders are in a virtual tie among white New Yorkers, Clinton holds a 40-point edge among minorities, including Latinos favoring her by a 62-to-22-point margin. The poll falls in line with similar survey from Quinnipiac University and Fox News, but varies from a PRRI/The Atlantic survey released last Thursday.

The Public Research Institute's poll finds Sanders may be closing the Latino gap ahead of New York's April 16 primary. Left-leaning registered Latino voters as split between the candidates with Sanders holding a slim one-point advantage over Clinton.

Six-in-ten Latinos viewed Clinton favorably, compared to about 54 percent for Sanders. Latinos equally represent 12 percent of Sanders and Clinton voter bases, respectively.