Just days after the commander of U.S. Kadena Air Base, near the city of Okinawa, promised parents their children’s schools were safe from dioxin contamination, a further 50 chemical barrels have been unearthed from adjacent land and a retired U.S. Air Force major has come forward with claims the school grounds are located near a former dump-and-burn site for waste that included military defoliants.

In addition, a growing number of parents affiliated with the base believe their children’s serious illnesses may have been caused by dioxin exposure.

Last Tuesday, at a hastily convened meeting, 18th Wing Commander Brig. Gen. James Hecker admitted to parents that he ought to have informed them of the contamination next to the playing fields of Bob Hope Primary School and Amelia Earhart Intermediate School as soon as he learned of the problem last summer.

However, he reassured his audience of about 100 U.S. service members and their dependents that there were no indications the base itself was polluted and stated his staff were doing all they could to protect children from any harm.

However, a few days after that meeting, members of the Okinawa Defense Bureau unearthed a further 50 barrels on land that, until 1987, had been part of the neighboring base. Similar to the 33 barrels previously discovered, some of the latest batch bore the logo of the Dow Chemical Co. One of the barrels was marked “malathion” — an insecticide — in katakana, suggesting it may have been used by Okinawan maintenance staff employed by the installation.

On Friday, in response to the latest discovery and the jump of the current barrel tally to 83, Defense Minister Itsunori Onodera told local television reporters the government will investigate the contents of the barrels and gather details about the factory where they were manufactured.

He added that the full details and background of the discovery have not yet been confirmed.

Checks on the previous barrels unearthed near the base revealed high concentrations of dioxin and herbicide. In December, officials in the city of Okinawa also announced that surface soil contained elevated levels of arsenic.

Fears that toxic barrels may also lie beneath the school grounds themselves have been heightened by allegations by Ronald Thomas, the retired U.S. Air Force major.

As a teenager in the late 1960s, Thomas lived on the base and he claims that he regularly transported empty barrels to land near to where the schools now stand. At that time, the land was used as an unofficial dump site.

“They were 55-gallon (208-liter) and, on occasion, 30-gallon (114-liter) drums. You could smell the chemicals and a few were stenciled with ‘Defoliant’ in white with ‘Property KAB Special Services,’ ” Thomas told The Japan Times in a recent interview.

Some of the drums were buried, while others were burned or sold to local Okinawan residents, Thomas said.

He is unsure whether the barrels he transported held Agent Orange — the Vietnam War defoliant manufactured by Dow Chemical and other companies in the 1960s and ’70s. More than 250 U.S. veterans claim Agent Orange was sprayed, stored and buried on Okinawa during the Vietnam War, but the Pentagon denies it was ever present on the island.

Thomas said he contacted both Kadena Air Base and the U.S. military newspaper Stars and Stripes with his account and urged them to take action. Neither followed up on his recommendations.

“They don’t want to open that Pandora’s box up. It’s better for the (base authorities) and the Japanese government to say there is no problem,” Thomas said.

More than 10 parents whose children developed serious illnesses while living on Okinawa bases have expressed fears that contamination at the two schools may be to blame. Many of the sicknesses from which they are suffering include those known to be caused by dioxin exposure — birth defects, autoimmune disorders and childhood cancers.

Telisha Simmons, who lived on the island between 2011 and 2012, is just one of the mothers who worries that her children’s ill health may have been caused by base contamination.

“I am disgusted that this information has been kept from us. Not even after my daughter was diagnosed with bone tumors and my son with a brain cyst were we informed,” she told The Japan Times.

Simmons’ family doctors have been unable to offer an explanation for her children’s illnesses. Her son attended Bob Hope Primary School and often played on its fields.

“He went out in all weather conditions and at times was wet, muddy and dirty when getting home. It makes me sick that this has been kept hush-hush,” she said.

At Tuesday’s meeting with the 18th Wing commander, the base authorities told parents that all tests for toxins on the schools had come back clear. However, many parents questioned whether the 15-cm-deep soil samples were sufficient to detect contamination. Some of the barrels discovered on the nearby civilian land had been buried several meters below the surface.

The base announced it will conduct further tests on the schools’ grounds this weekend and it provided a telephone number to contact for any parent with sick children. At least one of the schools announced it will also keep students indoors while work to unearth the barrels continues on the other side of the base perimeter fence.