The dioxin content of air over an industrial district near the U.S. Atsugi Naval Air Facility in Kanagawa Prefecture is 35 times the government standard, the Environment Agency and the Kanagawa Prefectural Government said Wednesday.

The two bodies believe the cancer-causing agent is being emitted by an industrial waste incinerator run by Enviro-Tech, a private industrial waste disposal firm in close proximity to the military facility.

In the most recent study, conducted for 56 days from late December until late February, officials found the highest level of dioxin to be 21 picograms per cubic meter of air, compared with the government’s guideline of 0.6 picograms introduced on Jan. 15.

But this value is less than half the unprecedented level of 54 picograms logged during a similar study last summer. A picogram is a trillionth of a gram.

The latest study found that dioxin exceeded the environmental standard at all three sites tested. The highest levels were found at an industrial area 150 meters from the controversial firm’s smokestack.

Three rivers near the incinerator were also tested for the carcinogen. In two water samples and one sediment sample taken upstream, dioxin levels tested at .41 picograms, which is within the government’s standard of 1 picogram per liter.

But downstream samples told another story, as water from a majority of the 11 sites surveyed, mainly along the Date River, exceeded the standard.

Dioxin concentrations in downstream river sediment were also high, with an average of over 30 picograms per gram of sediment and a high of 92 picograms.

The agency initiated a joint study with the U.S. military on March 11 that will track dioxin in the air at four points around the base until next year, at the earliest.

In part, the study will gauge the effect that filters to be installed on the incinerators this month will have in reducing dioxin concentrations in the air.

The U.S. government filed a civil suit against Enviro-Tech at the end of March, charging that the incinerators obstruct its right to use the property.