Subic Naval Base, Philippines - It has been 13 years since Luisa Devillena’s son Romar died of leukaemia at the age of four. She remembers how “sweet” Romar was, recalling how he frequently ran a fever and had swollen joints even as a one-year-old.

Devillena’s eyes turned watery recounting how her firstborn would insist on playing, even when a catheter tube from chemotherapy dangled from his arm.

Despite medical advice, the family insisted that Romar receive full treatment for Stage 3 cancer of the bone marrow - even if that meant selling his paternal grandparents’ small piece of land and moving into rental housing in Olongapo City, a highland slum north of Manila.

Romar’s doctors could not be certain about the cause of his cancer. But they told Devillena that exposure to carcinogenic contaminants was likely to blame. She suspects that frequent trips during her pregnancy to the beach in nearby Subic, a former US naval base, was a contributing factor. Her suspicions grew after learning about the death of a neighbourhood child with cerebral palsy and other recorded cases of child abnormalities in Olongapo.

On Monday, the United States and the Philippines signed a new military agreement expanding the presence of American troops in the country, shortly before the arrival of President Barack Obama in Manila.

‘A legacy of toxic waste’?

But environmentalists and watchdog groups are urging a closer look at the provisions of the new deal. They note that the US refused to clean up toxic waste it left behind at former bases under the old agreement, which they believe caused serious health issues in nearby communities.

“When they left the two bases, it became apparent to us and many other groups that the US also left behind a legacy of toxic waste,” Von Hernandez, executive director of Greenpeace Southeast Asia, told Al Jazeera. “This was associated with irresponsible use, storage, as well as disposal of hazardous materials inside those former bases.”

As the Philippines enters into a new military deal with the US, Hernandez said it should use the opportunity “to remind the US government of their responsibilities, and their liabilities, over these toxic legacies”.

In a 1992 report to the US Congress, the US government acknowledged that it had “identified contaminated sites and facilities that would not be in compliance with US environmental standards” at Subic and Clark, two of the largest military bases outside of the US until 1992.

The report said that “only 25 percent of the five million gallons of sewage generated daily” was treated. Lead and other heavy metals used in ship repair were drained directly into Subic Bay, or buried as landfill - in violation of US standards which require that such heavy metals “be handled and disposed of as hazardous waste”.

The report also revealed that during its operation, Subic’s power plant contained “unknown amounts of polychlorinated biphenyl (PCB) and emits untreated pollutants directly into the air”, in conflict with the US’ own clean air standards.

Al Jazeera sought comment, by phone and email, from Kurt Hoyer, spokesman for the US embassy in Manila. Hoyer did not respond to the requests. Al Jazeera also visited the US embassy but was told that the request would be forwarded to the communications office.

Contaminants that ‘just won’t go away’

Because US troops were forced out of the Philippines after the 1991 eruption of Mount Pinatubo and a subsequent vote by the Philippine Senate to reject the bases treaty, the US military did not continue its investigations into the toxic contamination.

But communities near the base have reported a “high incidence” of birth abnormalities and “impaired intelligence” among local children. There were also reportedly high levels of kidney diseases among some 700 families monitored by the International Institute of Concern for Public Health near Clark Air Base in Angeles City, as well as reported cases of asbestosis among shipyard workers.

“There is a preponderance of evidence that it is a heavily polluted base,” said Myrla Baldonado, a Chicago-based leader of the People’s Task Force on Bases Cleanup, an environmental watchdog group. “These contaminants just won’t go away,” she said. “They will keep coming up, because the sites have not been cleaned up.”

In 2000, a group of individuals filed a class action lawsuit in the Philippines against the governments of the Philippines and the US, claiming damages for health complications and even death. One complainant, Virginia Guevarra of Olongapo, said her daughter’s cerebral palsy was caused by contaminants at Subic. The lawsuit was not successful.

No obligations

Saul Bloom, executive director of Arc Ecology, a technical services provider to communities affected by environmental problems, has conducted studies on former US military bases in San Francisco and the Philippines. The previous bases agreement between the Philippines and US stipulated that the latter “is not obligated to return relinquished facilities to their original condition”, he said, thus allowing the US government to refuse to clean up.

In a study conducted at Clark and Subic, Bloom told Al Jazeera that he identified at least 50 sites with potential toxic contaminants. However, Bloom added, no studies were conducted to determine whether there was a pattern of health problems in the affected communities.

Doctor Gene Nisperos, of the Health Alliance for Democracy in the Philippines, told Al Jazeera that despite the merits of the case, the Philippines “has no power” to hold the US military accountable in court for dumping the toxic waste.

Bloom agreed, saying the US government holds that it is “exempted” from prosecution because of the bases agreement’s legal provisions.

According to the US General Accounting Office, the agreement also does not contain a claims provision, which would cover injuries to persons and property arising from environmental problems caused by the US presence.

The Philippine government has been reticent in pressing the US to take responsibility for the cleanup, said Greenpeace’s Hernandez. In 2012, the US was accused of dumping 189,500 liters of domestic waste and about 760 litres of a mixture of water, oil and grease from a naval ship. But, Hernandez said: “The problem has been conveniently swept under the carpet by both parties.”

‘We don’t really need the US troops’

Bloom said the Philippines would be better off negotiating a military agreement with cleanup provisions. “Get a good, signed environmental agreement right now, early in the process, before the problems arise later,” he said.

Yet both the Philippine and US governments refused to release the details of the agreement - a move that alarms activists.

Devillena, the mother who lost her son to cancer, is unhappy at the return of US troops - and still worries about her family’s health. Since the death of Romar, it took her and her husband Ronald another four years to have a baby, because they were worried about birth defects.

Their son Vince Jay is now a healthy 10-year-old. According to Devillena, he is the spitting image of Romar - who would have been 18 in June. In 2007, they had another child, Maria Ceelyn, who is now in first grade.

“If you ask me, we don’t really need the US troops,” Devillena said. “We can stand on our own. Not everyone benefited from their presence here before. When they left, we still managed to survive. So I don’t think their return will make a difference.”