When hundreds of angry and anxious Portlanders showed up to a community forum at Cleveland High School last week, Portland Public Schools officials had some good news.
Controversy was just beginning over whether a nearby glass factory had been pumping the neighborhood air full of the heavy metals cadmium and arsenic for years—a possibility raised by state Department of Environmental Quality monitoring last October. But air quality at Cleveland and four other nearby schools, PPS officials told parents, had revealed no sign of the carcinogens.
“Indoor air testing during the school day on Feb. 5 at Abernethy, Cleveland, Grout, Hosford and Winterhaven schools came back with no detectable levels of arsenic or cadmium,” a February 9 news release from the district said.
It was a welcome fact—reported far and wide—but not particularly surprising. Bullseye Glass had pledged to cease burning cadmium and arsenic since being told February 1 about the air quality findings, which found arsenic levels at 159 times state air quality benchmarks, and cadmium levels that were 49 times higher. (The company’s since agreed to suspend use of chromium.)
But here’s the thing PPS didn’t mention about its results: The tests it ordered up weren’t able to rule out the possibility arsenic and cadmium levels exceeded state safety benchmarks in the five schools. They weren’t precise enough.
A copy of the actual testing results [pdf] from the schools, obtained by the Mercury, shows that the testing PPS contracted for couldn’t detect arsenic or cadmium at the levels at which DEQ officials begin to show concern. For arsenic, the state safety benchmark is 0.2 nanograms per cubic meter (ng/m3). For cadmium, the benchmark is 0.6 ng/m3.
According to Oregon Health Authority toxicologist David Farrer, those thresholds represent levels of the carcinogens at which continuous exposure could result in a 1-in-a-million chance of contracting cancer over a lifetime. But the tests PPS ran wouldn’t indicate a positive hit for arsenic or cadmium at those levels. They wouldn’t have picked up the metals until they reached approximately 3 ng/m3. That’s 5 times the benchmark for cadmium, and 15 times the benchmark for arsenic.
That casts the school district’s assurances its schools had no detectable cadmium or arsenic in a new light. It’s not that there’s any proof that those metals are in the schools, but PPS can’t honestly say they’re not there in potentially troublesome amounts, either.
We asked PPS spokesperson Jon Isaacs about this, as well as Doug Hancock, a project manager with PBS Engineering and Environmental, the firm that carried out the school testing. Isaacs began looking into it, and Hancock said he couldn’t speak with the Mercury. Then Hancock sent a letter [pdf] to PPS today which helped answer our question.
The letter points out that arsenic and cadmium, at the elevated levels DEQ officials turned up near Bullseye, would have shown up on PBS’s tests. And it also contends that the peak concentrations DEQ found “are still significantly lower than the OSHA cadmium and arsenic permissible exposure levels (5,000 nanograms per cubic meter and 10,000 nanograms per cubic meter).” But PBS acknowledges that its method, involving “7 to 8 hours” of monitoring at the five Portland schools, achieved a detection limit of “approximately 3 nanograms per cubic meter air,” well above the state benchmarks.
We’ve asked whether the school district knew this when assuring parents neither cadmium or arsenic were found at its schools, but Isaacs wasn’t immediately able to answer that question.
MORE COVERAGE:
State Finds Alarmingly High Arsenic, Cadmium Levels Near Two SE Portland Schools
Bullseye Glass Has Suspended Use of Arsenic and Cadmium Because of Air Quality Concerns
Portland Public Schools Is Ordering Air Tests Because of Arsenic, Cadmium Concerns: “We Need A Public Meeting”
Soil Near Bullseye Glass Contains Arsenic and Cadmium—And Other Things Officials Told Parents Thursday
Essential Pollution Controls Lacking at Two Glass Plants Blamed For Cadmium Emissions
Thanks for bringing this to public attention.
Can you fix the link to the test data? Looks like it is missing part of the filename.
Beyond that, the DEQ measured concentrations on the order of 30 ng/m^3, so the detection threshold is enough to know that levels would be 10X less than what was measured when Bullseye was operating. I’m concerned by the “potentially troublesome amounts” language – what the heck does that mean? Above airshed benchmarks? That is sensitive enough detection to say with confidence that levels are below the 1 in 60,000 lung cancer risk for As, and 1 in 200,000 risk for Cd. It is also one fifth the CalEPA threshold for likely health effects for As, and one third the same threshold for Cd. So it’s adequate for knowing that health risks when the tests were conducted were minimal. Of course, it can’t say anything about levels when Bullseye was operating with those metals, since it happened afterward.