Dorado, Puerto Rico (CNN) A tall chain link fence, shrouded in vines, surrounds an aging water well tucked away in this small town just west of San Juan. A metal sign carries a warning in Spanish to anyone who approaches: "Danger. Do Not Enter."

That doesn't stop Juan Carlos Oquendo, 39, from peeling away a corner of the fence and jumping inside. He's brought a van load of containers to fill.

But what he doesn't fully understand is that water from the faucet is potentially contaminated with industrial chemicals that can cause serious health issues

"I'm going to drink it. I've drank it before. It tastes fine," Oquendo told CNN as he filled his jugs. "If I don't drink water I'm going to die. So I might as well drink this water."

Oquendo stresses that he's willing to take this chance because access to clean water in his neighborhood has been extremely difficult for much of the last month since Hurricane Maria wiped out the water system on the island.

Just before CNN spotted Oquendo at the water well site, a team of scientists from the US Environmental Protection Agency was collecting water samples from the well.

The EPA is focused on this site because the well sits on what's called the Dorado Groundwater Contamination Site, which was listed in 2016 as a Superfund site in Puerto Rico. The area is polluted with industrial chemicals, including tetrachloroethylene and trichloroethylene, "can have serious health impacts including damage to the liver and increasing the risk of cancer," the EPA said when it designated the site as contaminated.

Gary Lipson, the EPA Incident Commander working in Puerto Rico in the aftermath of Hurricane Maria, says nearby residents have been drinking potentially contaminated water from this well.

"It's a concern both in public health and perception. We understand that people are hurting right now. We understand there are a lot of thirsty people out there, and they are accessing whatever water they can," Lipson told CNN. "We are trying to ascertain if it poses any hazards or not."

The EPA has "provided information to the Dorado community emphasizing that they must avoid using wells on the western portion of the site," the agency said in a statement Sunday.

That is the same area where CNN saw Oquendo tapping into a well.

EPA teams gathered water samples this weekend from at least six wells inside the Dorado Superfund site. A series of tests will determine the contamination levels.

EPA officials say the results could be made public by the end of the week.

Photos: Hurricane Maria slams the Caribbean An apartment building is missing a wall in San Juan, Puerto Rico, on Monday, September 25, nearly a week after Hurricane Maria devastated the US commonwealth. Power is still out in most places, and communications remain almost nonexistent on the island of 3.4 million people. Hide Caption 1 of 36 Photos: Hurricane Maria slams the Caribbean Yancy Leon rests at the Luis Muñoz Marin International Airport near San Juan on September 25. She's been waiting in line for two days to get a flight out. Hide Caption 2 of 36 Photos: Hurricane Maria slams the Caribbean An aerial view shows the flooding in San Juan on September 25. Hide Caption 3 of 36 Photos: Hurricane Maria slams the Caribbean People collect water from a natural spring created by landslides in Corozal, Puerto Rico, on Sunday, September 24. Puerto Rican Gov. Ricardo Rosselló said the island faces a humanitarian crisis. Hide Caption 4 of 36 Photos: Hurricane Maria slams the Caribbean An aerial view shows a flooded neighborhood in Catano, Puerto Rico, on Friday, September 22. Hide Caption 5 of 36 Photos: Hurricane Maria slams the Caribbean A man cleans a muddy street in Toa Baja, Puerto Rico, on September 22. Hide Caption 6 of 36 Photos: Hurricane Maria slams the Caribbean A man walks on a highway divider while carrying his bicycle through San Juan, Puerto Rico, on Thursday, September 21. Hide Caption 7 of 36 Photos: Hurricane Maria slams the Caribbean A shack is destroyed in San Juan on September 21. Hide Caption 8 of 36 Photos: Hurricane Maria slams the Caribbean A gas station's sign is damaged in Punta Cana, Dominican Republic, as the hurricane passed just north of the country on September 21. Hide Caption 9 of 36 Photos: Hurricane Maria slams the Caribbean Rescue workers drive through a flooded road in Humacao, Puerto Rico, on Wednesday, September 20. Hide Caption 10 of 36 Photos: Hurricane Maria slams the Caribbean A mattress that fell from the third floor is surrounded by debris outside a San Juan apartment complex on September 20. Hide Caption 11 of 36 Photos: Hurricane Maria slams the Caribbean Damage is seen in Roseau, Dominica, on September 20. Hide Caption 12 of 36 Photos: Hurricane Maria slams the Caribbean People walk through the destruction in Roseau on September 20. Hide Caption 13 of 36 Photos: Hurricane Maria slams the Caribbean San Juan is shrouded in darkness after the hurricane knocked out power to the entire island of Puerto Rico. Hide Caption 14 of 36 Photos: Hurricane Maria slams the Caribbean Power lines are scattered across a road in Humacao, Puerto Rico, on September 20. Hide Caption 15 of 36 Photos: Hurricane Maria slams the Caribbean Residents move aluminum panels from an intersection in Humacao on September 20. Hide Caption 16 of 36 Photos: Hurricane Maria slams the Caribbean Rescue vehicles are trapped under an awning in Humacao on September 20. Hide Caption 17 of 36 Photos: Hurricane Maria slams the Caribbean Trees are toppled outside the Roberto Clemente Coliseum in San Juan on September 20. Hide Caption 18 of 36 Photos: Hurricane Maria slams the Caribbean Members of a rescue team embrace as they wait to help in Humacao on September 20. Hide Caption 19 of 36 Photos: Hurricane Maria slams the Caribbean A tree is damaged in Fajardo, Puerto Rico, on September 20. Hide Caption 20 of 36 Photos: Hurricane Maria slams the Caribbean Debris is strewn across a Fajardo street on September 20. Hide Caption 21 of 36 Photos: Hurricane Maria slams the Caribbean A woman closes her property in Naguabo, Puerto Rico, hours before Maria's arrival. Hide Caption 22 of 36 Photos: Hurricane Maria slams the Caribbean People take shelter at Puerto Rico's Humacao Arena on Tuesday, September 19. Hide Caption 23 of 36 Photos: Hurricane Maria slams the Caribbean Two girls play on cots at the Humacao Arena. Hide Caption 24 of 36 Photos: Hurricane Maria slams the Caribbean Waves crash in San Juan as the hurricane neared Puerto Rico on September 19. Hide Caption 25 of 36 Photos: Hurricane Maria slams the Caribbean People pray in Humacao on September 19. Hide Caption 26 of 36 Photos: Hurricane Maria slams the Caribbean A street is flooded in Pointe-a-Pitre, on the French Caribbean island of Guadeloupe, on September 19. Hide Caption 27 of 36 Photos: Hurricane Maria slams the Caribbean People stand near debris at a restaurant in Le Carbet, Martinique, on September 19. Hide Caption 28 of 36 Photos: Hurricane Maria slams the Caribbean People in Luquillo, Puerto Rico, board up windows of a business on September 19. Hide Caption 29 of 36 Photos: Hurricane Maria slams the Caribbean A boat is overturned off the shore of Sainte-Anne, Guadeloupe, on September 19. Hide Caption 30 of 36 Photos: Hurricane Maria slams the Caribbean Cars line up at a gas station in San Juan on September 19. Hide Caption 31 of 36 Photos: Hurricane Maria slams the Caribbean A motorist drives on the flooded waterfront in Fort-de-France, Martinique, on September 19. Hide Caption 32 of 36 Photos: Hurricane Maria slams the Caribbean Floodwaters surround cars in Pointe-a-Pitre on September 19. Hide Caption 33 of 36 Photos: Hurricane Maria slams the Caribbean Soldiers patrol a street in Marigot, St. Martin, as preparations were made for Maria on September 19. Hide Caption 34 of 36 Photos: Hurricane Maria slams the Caribbean People buy provisions in Petit-Bourg, Guadeloupe, as the hurricane approached on Monday, September 18. Hide Caption 35 of 36 Photos: Hurricane Maria slams the Caribbean Customers wait in line for power generators at a store in San Juan on September 18. Hide Caption 36 of 36

One well on the Dorado Groundwater Contamination Site has been approved by the Puerto Rican water authority and federal officials for public use. Thousands of residents wait in a shopping center parking lot to fill up containers of water.

Puerto Rico Gov. Ricardo Rossello also says the territory's Department of Health has tested this water and deemed it safe.

"What people need to know is they did pass the Clean Water Act and standard," Gov. Rossello told CNN. "If it's non-drinking water, we're not going to be serving it. But if it complies with the Clean Water Act, it is going to happen."

CNN reviewed documents published in 2016 as part of the EPA's move to designate the Dorado Groundwater Contamination Site as a Superfund location.

It's unclear exactly which parts of the area may be contaminated.

"The EPA is in the process of examining the precise extent and location of this contaminated groundwater plume," said the agency's news release on Sunday. "Data gathered by EPA in 2015 showed that some wells in the western part of the area are contaminated, while some wells in the eastern portion of the area meet drinking water standards. The entire area, including many wells regardless of contamination levels, was included in the designated Superfund site boundaries as a precautionary measure because groundwater contamination can move over time and EPA wants to study the entire area."

David Carpenter, Director for the Institute of Health and the Environment at the University of Albany, said "it is reasonable to distribute this water under the present circumstances" but there are no safe levels for carcinogens in water.

"It is certainly likely that these wells will have contamination," Carpenter said after reviewing EPA documents.

The documents show that three different wells contain concentrations of toxic chemicals known as PCE and TCE that exceed the agency's maximum contaminant levels for drinking water, said Erik Olson, the Health Program Director with the Natural Resources Defense Council in Washington, DC.

Olson also says the documents show the Superfund site contains karst limestone, "which is notorious for allowing contamination to spread easily and quickly."

"It is irresponsible to not make every effort humanly possible to find and provide safe drinking water as soon as possible," Olson wrote to CNN in an email.

Juan Carlos Oquendo returned to his home in Dorado and unloaded the bottles he filled at the well. The home he shares with his siblings and mother was severely damaged in the hurricane.

The roof was ripped off the second floor, and the family is still living without electricity and running water.

Oquendo's mother, Carmen Rojas, recounted the moment when the house started coming apart in the storm. Since then, she says, emergency officials have delivered only two small packages of water to residents in her neighborhood.

Rojas, 68, says she started drinking the Dorado Superfund well water about two weeks ago and immediately started feeling stomach pains.

"I don't know what's causing it," she says, "but it might be because of the water."

On Monday afternoon, CNN returned to four sites around Dorado and found that security guards have now been stationed at each. One of the wells was guarded by two agents with Puerto Rico's Special Investigations Bureau. Private security guards were stationed at the remaining wells, cutting off any further access to these sites by the general public.

Also, near these wells CNN witnessed a small convoy of military vehicles and personnel including FBI agents, handing cases of bottled water to cars driving by.

On Monday, the EPA announced that results of tests on samples from wells on the Dorado Groundwater Contamination Site should be available on Tuesday and the results of the more serious chemical analysis are expected early next week.