Hello,
I am a glass artist in the UK and rely on Bullseye glass for my work. In the UK we only  get 3 types of  fusible glass imported - Bullseye, Spectrum (now Uroboros) and  float-compatable. Most people here work with either Bullseye or Spectrum (which is closing with Uroboros taking up the slack) so without these manufacturers many artists and hobyists will have to stop their glass fusing. Without hobyists there will be less oportunity for artists to supplement their income by teaching.
In my own case, I was made redundant after long-term illness. Having now recovered enough to do some work I have found getting a  suitable job where my on-going health problems are tolerated is nigh on impossible. I have now invested my money in setting up my own glass business. 
Much of my existing equipment is made in the USA and due to all the uncertainty surrounding the continued production of US  fusing compatable glass  I have just put off buying a larger kiln (Paragon which is a US company), a lap-grinder (Glastar which is a US company) and ring saw (Gemini Saw Co which is a US company). Replacement grinding discs and blades are also imported from the USA.  I have been lucky enough to take classes with some US-based instructors.  As you can see the loss of  the US art glass industry will have an economic impact in the USA beyond the glass manufacturers. In my own case, without compatible fusing glass I will have lost the money I have already invested and have to go on welfare.  
Bullseye was in compliance with the old code. We all want Portland to have clean air (the glass manufacturers and their employees live there afterall). Even so, when notified of any problem Bullseye initiated action to address it, from voluntarily suspending using certain metals to arranging baghouses to be installed. However, in the case of Bullseye, the Cease and Desist issued by the Governor meant they had to decrease their glass production by some 80%, making it very difficult to raise the money by selling glass to install the baghouses. Even with sufficient capital, these adjustments can't be made overnight as these baghouses are custom-built. 
Please make any decisions based on facts rather than being media-led.For example it is still being reported that Bullseye is releasing harmful chromium, but the report stating that 5,498 pounds of raw hexavalent chromium compounds on site at Bulleye was an error based on an error in the Fire Marshal's HSIS. Apparently "chromite" (Cr3) autocorrects to "chromate" (Cr6). 
 Re the Bullseye baghouse and chromium batch test result, the firm that did the testing said in their report that the test results were not consistent and that no conclusions could be made based on those results. There are concerns regarding how the test was conducted and results (which DEQ acknowledge) which on at least one occassion showed more Cr6 in the test results than CR3 going into the furnace.
While Bullseye could certainly have been emitting some amount of metals from unfiltered furnaces and it's important they addressed their patch (which they immediately and continue to do so)  From a basic chemistry standpoint look at the boiling temperature point of a compound and its decomposition temperature. Most colorants are going to have boiling points under the glass melting point and just go into solution and be trapped within the glass. Most of the concerns are with the dust of the colorants getting loose from the crucible in the thermal updraft of the furnace before the glass melts, and before the colorant can be trapped in solution. Baghouses will address this.
It should also be noted that The USFS moss study did not sample around the Brooklyn railyard. (Nor can it account for wind direction.) Uroboros is also near a train yard. Particulate matter is created during the incomplete combustion of diesel fuel. Its composition can include hundreds of chemical elements, including sulfates, ammonium, nitrates, elemental carbon, condensed organic compounds, and and heavy metals such as arsenic, selenium, cadmium and zinc. 
The daycare is literally surrounded on three sides by the rail yard. Across the street is Lehigh Southwest Cement. Mention CR6 and everyone immediately thinks of high temperature industrial processes. All the cement across the street is a product of high temperature industrial processes - it's just not processed across the street. Same thing with the fly ash that contains all the heavy metals*- it was produced elsewhere. There is a rail car shed there. The shed allows for rail cars to have a roof overhead when they unload. It is also not protected like the truck transfer facility with baghouse filtration etc. The shed is open on both ends. When the wind blows it will blow through the shed picking up any concrete or fly ash that has been spilled. 
In summary, please give the glass companies clear and set guidelines and allow them time to make alterations. Allow them to stay in business. Please consult with a glass scientist to find out what can and can't happen in a kiln. Measure wind direction. For the sake of the people of Portland also investigate beyond the glass industry and put any pre-conceptions aside.  Thank you

* (depends upon the specific coal bed makeup, but may include one or more of the following substances in quantities from trace amounts to several percent: arsenic, beryllium, boron, cadmium, chromium, chromium VI, cobalt, lead, manganese, mercury, molybdenum, selenium, strontium, thallium, and vanadium, along with dioxins and PAH compounds.)