Since officials announced the discovery of unhealthy levels of arsenic and cadmium in the air in Southeast Portland earlier this month, they've released a lot of new information about airborne heavy metals and the associated public health risks.
Here's what you should know at this point:
The discovery came from testing tree moss.
The original detection of heavy metals came from a unique study by U.S. Forest Service researchers who gathered hundreds of moss samples from around Portland and tested them for various contaminants. The moss samples flagged two hot spots for cadmium in Southeast Portland and North Portland, as well as some hot spots for lead and nickel that are still being analyzed.
Follow-up air testing by the Oregon Department of Environmental Quality in Southeast Portland found levels of arsenic at 159 times the state benchmark for healthy air and cadmium levels at 49 times higher than the health benchmark.
Colored glass-makers are suspected but not proven sources.
DEQ officials linked the pollution they found in Southeast Portland to the Bullseye Glass facility, which uses metals to make colored glass for art and architecture. But they say the nearby rail yard also likely contributed some of the cadmium, which is a component of locomotive exhaust.
The agency just started testing the air in North Portland on Friday and won't have results until April. So for now officials only have moss sampling data showing a second cadmium hot spot a quarter-mile from another colored glass-maker, Uroboros Glass.
No one tested the actual emissions from these glass facilities so it is unknown exactly how much of the metals detected in moss and in the air came out of the companies' furnaces.
There are health risks for people exposed – but they're complicated.
Officials say the state's health benchmarks are very conservative and being exposed to high levels of heavy metals doesn't mean people will definitely experience health effects. The people at the greatest risk, they say, are those who spent the most time within about a half-mile of the glass factories.
Oregon Health Authority toxicologist David Farrer says the levels of cadmium and arsenic detected in Southeast Portland are high enough to raise the cancer risk from one case in a million people to 1 in 10,000. That's still low, he says, but it's higher than what the state says is acceptable.
OHA's preliminary analysis of available cancer data did not find an elevated incidence of lung or bladder cancers in the affected area of Southeast Portland. The agency has more information on health risks here.
The risks have been reduced.
Bullseye Glass has stopped using arsenic, cadmium and chromium in its operations and Uroboros Glass has stopped using cadmium and chromium (it hasn't used arsenic in 20 years). Both companies acted voluntarily; they were operating legally, using those metals in their manufacturing processes as permitted by state and federal laws.
Officials asked the companies to stop using chromium when they noticed both glass-makers used hexavalent chromium in their operations. They say that metal was likely released into the air as well but they don't know how much. Hexavalent chromium can cause anemia, asthma, skin allergies and lung and stomach cancers.
Now that the companies have stopped using these metals, officials say it's safe for people to spend time outdoors near the glass factories because air pollution clears quickly with rain and wind.
Medical experts say people can take additional precautions by eating a healthy diet with plenty of calcium, iron and folic acid to help protect the body against the negative effects of heavy metals.
Those exposed can have their urine tested.
Health officials say arsenic and chromium pass quickly through our body, but cadmium is deposited into the kidneys and stays there for awhile.
People who have been exposed can get tested for arsenic, cadmium and chromium in one urine test. It will only measure recent exposure (within hours or days) to arsenic and chromium but it can measure cadmium exposure within the past few years. The test doesn't distinguish between the healthy chromium (III) and the carcinogenic chromium (VI).
Oregon Health Authority has offered to help pay for testing and put new rule in place that allows healthcare providers to report the results to the state. They're hoping that will allow officials to start looking at the health effects across the city.
Some homegrown veggies may not be safe to eat but we don't know yet.
Officials have warned residents within a half-mile of the mapped hotspots for cadmium and arsenic to avoid eating vegetables grown in their gardens. That warning is a precaution at this point. The state still needs to review the results of its soil testing in Southeast Portland. Some people who are concerned about the soil in their yard are paying to have it tested through a private lab.
DEQ is doing more air and soil testing.
DEQ is testing the soil and the air in Southeast Portland for a long list of metals.
The agency has deployed additional air monitors in four locations in Southeast Portland: Winterhaven School, the daycare near Bullseye Glass called Children's Creative Learning Center, the parking lot next to Powell Park and northwest of Bullseye Glass at SE 20th Avenue and SE Haig Street. The agency is also collecting wind speed and direction near Bullseye Glass.
Soil sampling around Bullseye was completed Feb. 17. Sampling near Uroboros Glass just started Feb. 19. The first air and soil testing results will be available the week of March 7.
Portland public schools are also being tested.
Portland Public Schools performed air and soil tests at five schools in Southeast Portland. PBS Engineering & Environmental ran the tests on Feb. 5 at Abernethy Elementary, Cleveland High School, Grout Elementary, Hosford Middle School and Winterhaven K-8. All tested below the "minimum reporting limit" for arsenic and cadmium, the only two toxic pollutants tested at those schools.
PBS E&E also tested Harriett Tubman Middle School for arsenic and cadmium, and again, found levels below the level of concern. The report is expected to be posted to the Portland Public Schools website soon.
The tests at those schools were all conducted after Bullseye and Uroboros glass companies had stopped using cadmium in their operations. Uroboros had not been using arsenic for years, according to state officials.
Portland Public Schools asked PBS E&E to run tests at four additional schools: Boise-Elliott K-8, Lane Middle School, Lewis Elementary, and the Rose City Park campus of Beverly Cleary School. Those test results are expected this week (possibly as soon as Wednesday).
Air pollution rules allowed metals to go undetected for years.
Federal air pollution rules don't require Bullseye or Uroboros to test their pollution emissions or add pollution controls to the 2,000-degree furnaces they use to make glass. The federal rules are based in part on the size of the facility and how much material they process, and both plants are under the limit that would have triggered additional regulations.
The Environmental Protection Agency has told members of Oregon's congressional delegation that the two glass-makers were exempted from other pollution controls required for some glass-makers because they don't run their furnaces continually.
State officials say the lack of regulation created a blind spot for toxic air pollutants that were likely coming from the two facilities. In response to concerns raised by Gov. Kate Brown, Oregon DEQ is building an inventory of other facilities that might pose pollution concerns.
DEQ Director Dick Pedersen says he's working on a regulatory fix to the problem such as adding state-level rules that will require testing emissions and addition pollution controls as needed to smaller manufacturing facilities. Washington and California have similar rules in place already.
Portland officials are looking at local air pollution control options.
Portland Mayor Charlie Hales and Multnomah County Chair Deborah Kafoury recently sent a letter to Gov. Brown threatening to establish a local Portland metropolitan-area regional air pollution authority if DEQ didn't take sufficient action.
Regional authorities are allowed under an Oregon law passed in 1967. They must cover an area including at least 130,000 people and have support of at least two local governments (such as a city and county).
There is currently only one regional air authority - the Lane Regional Air Protection Agency (LRAPA), in the Eugene area. But as that agency's director, Merlyn Hough, told OPB recently, there used to be three – including one in Portland called the Columbia Willamette Regional Air Pollution Agency. It folded in 1973. The third was in the Salem area, called the Mid-Willamette Valley Air Pollution Authority. That agency made it to 1975.
Among the benefits of a regional air authority is local air quality data. LRAPA has seven monitoring sites - three in and around Eugene, one north of Eugene in Coburg, two to the south in the Cottage Grove-Creswell area, and one to the southwest in Oakridge.
There's still a lot we don't know.
The Forest Service moss study collected hundreds of samples from all over Portland and tested them for a variety of contaminants. That study is not yet complete and the maps of other pollution hot spots have not been publicly released. The Oregonian has built maps of arsenic, lead and nickel hot spots around the city based on some of the moss data.
DEQ officials say they have not yet received validated moss data for lead and nickel from the Forest Service. When the final data is available, the agency plans to do additional air monitoring. At a legislative hearing Tuesday, DEQ's Pedersen acknowledged another metals hotspot near Precision Castparts in Southeast Portland.