Trustee responses are in bold.
Question from Mr. Negron: I’m a bit thick, I think (we don’t agree, by the way). I can’t quite understand the difference between slag that might be a problem and slag that isn’t — for example, the fines pile. Is it the constituents (ie: different slag piles came from different types of metals processing)? Is it the size of the particles (in which case, it seems that the bottoms of each piles would have dust-sized particles from the weight of the pile, and those would present wind and infiltration problems)?
Response: Slag in the arroyo falls into two main categories, 1.) copper slag and 2.) lead slag. Lead slag is thought to be exposed near the west abutment to the bridge adjacent the main plant and copper slag makes up the remainder the material in Parker Brother’s Arroyo. (Arroyo). The slag in the Arroyo was previously quarried and processed for use as railroad ballast, sand paper grit and other uses by a third party company called Ogleby-Norton. As a result, there are various piles of slag of different sizes that remain on the site ranging from around 8 inches down to sand-sized material (i.e., “fines” pile). Material larger than 3/16 inch has been previously shown to be relatively inert and non-hazardous. “Problem” slag would be materials that can not be recycled, sold or otherwise incorporated easily into the remedy, are very dusty or have metal contents at concentrations above regulatory limits. The fines pile has been evaluated and it appears to have limited reuse value. The fines pile as well as lead slag will either be covered or excavated and placed in an on-site repository. Overall, dust and water infiltration issues are manageable with conventional engineering measures which include capping or removal.
The Work Plan for the site remediation includes activities to evaluate materials in the Arroyo. Evaluations are planned to determine what slag can be used in embankments or for other construction purposes such as asphalt and concrete. To be useable, the slag typically has to be relatively uniform in size, chemically stable and free from large amounts of fine particles. Following our evaluation, a plan will be prepared and submitted to TCEQ outlining the options available.
Question from Mr. Negron: I also think I read in the Draft Remedial Action Work Plan that storm water drainage and groundwater conditions ARE a part of the environmental issues to be resolved (for such reasons as infiltration and flow rate), and that the biggest problems on both counts are with the Parker Brothers Arroyo. Is that not true, and if it is, how does that square with what TCEQ replied with and what you’re saying below?
Response: Storm water drainage and ground water conditions are a part of the environmental issues to be resolved at the site. Since the Arroyo is not impacted with metals at levels that require specific cleanup measures per se, monies were not specifically allotted for cleanup of this area that is otherwise an eyesore. That being said, after looking at the issue, it is clear that storm water, surface drainage from the site and groundwater, if managed together, create a sustainable, long-term solution for the Arroyo that can have tremendous public benefit. We believe that rehabilitation of the Arroyo needs to be considered so that it does not remain an eyesore and that actions taken to control flooding mesh with the other remedial measures considered for the site.
The remedial options considered by TCEQ focused on surface exposure and groundwater contamination. The secondary-level issues of visual impact, flooding and control of up-stream infiltration could not be reasonably anticipated when the conceptual remedy was reviewed by TCEQ and therefore there are some differences in approach to consider as the site is investigated and design alternatives are considered. Analysis by our engineers suggests that alternatives which incorporate measures in the Arroyo could be implemented that serve to improve the drainage, beautify and increase the value of the property and potentially help reduce long-term cost.
These alternatives are being evaluated as part of the design and considering the visual impacts, conversion of the Arroyo from its current configuration and unproductive use to possibly a viable public green space, waterway with trails and a bike path, is an opportunity the Trust believes is worth pursuing along with other measures to ensure the remediation is protective and an asset to the community.
Question from Mr. Negron: From the presentation, it was extremely informative, especially the part about the Rocky Mountain Arsenal portion of the Encycle Waste. I cannot find it online, which I expected to, so the only detail I find in my notes is the narrowing down of the waste to 15 tons of solvents/pesticide between 1992 and 1997. That in the context of the overall waste doesn’t sound like much, but then again …
Response: The presentation from the October 19, 2010 Community Meeting has been reposted to the Recasting The Smelter website and is available for review. The information related to the wastes shipped to ENCYCLE from the Rocky Mountain Arsenal was based on a review of shipping records. These records indicated that approximately 91.9 tons (in one shipment) of solvent and pesticide wastes and 4200 tons of incinerator brines (or waste treatment leachates) were shipped from the Rock Mountain Arsenal between 1992 and 1997. Given the feed rate through the plant the volume of materials burned is extremely small compared with the total feed to the smelter. Any remaining metal that was not recovered would be only a trace amount incorporated into slag.
Question from Mr. Negron: Did we know the chemical names? If so, how? Are we depending on the manifests from Encycle, which already had been accused of “sham recycling”?
Response: The waste manifests were prepared by the organizations shipping the waste, not ENCYCLE. Under the USEPA hazardous waste regulations it is in the best interest of the organization shipping the wastes to provide an accurate description. The chemical names are listed on the manifests using USEPA defined waste codes. These codes are very specific for the chemicals present in the waste and/or the nature of the waste.
Question from Mr. Negron: Do we know the exact dates?
Response: The shipping dates are listed on the manifests.
Question from Mr. Negron: Will it ever be possible to know details: How long did it take to burn (15 mins, two days?); how was it handled between the tanker and the smelter (pumped straight in through a hose? mixed with dirt and sent dripping on the conveyor?)
Response: Based on the review of the documents on the EPA website, the materials shipped to ENCYCLE were mixed with copper concentrate and other solid materials to render them acceptable to the smelting process prior to shipment from ENCYCLE. The records do not demonstrate that materials were transferred directly from a tanker to the smelter. Given the operating temperature and conditions in a smelter, solvent and pesticide wastes were combusted upon addition to the smelter; they would not be retained in the smelter. However, based on a standard engineering calculation that takes into account the size of the CONTOP smelter, the smelter operating conditions and the average feed rate, it is estimated that the average retention time of concentrate in the smelter was approximately one hour.
Question from Mr. Negron: How toxic is the material (for example, depending on the substance, I can see a truck full of nerve gas if it ruptured forcing the evacuation of half the city — more or less — I’ve seen trainloads of sulfuric acid, for example, cause massive panic over the threat of rupture)
Response: The materials shipped to ENCYCLE were incinerator brines (or waste treatment leachates) generated during the destruction of chemicals produced and stored (including nerve agents) at the Rocky Mountain Arsenal. No nerve agents were shipped from the arsenal.
All of the materials listed as on the manifests have defined toxicities. None of these materials exhibit toxicities approaching nerve agents.
Question from Mr. Negron: Does it lose the toxicity at temperature, or could the stack for 15 mins or two days been spreading pesticide/solvents tainted smoke, and for how far, since we probably won’t know wind/dispersal patterns for that time period?
Response: Given the operating temperature and conditions in a smelter, solvent and pesticide wastes were combusted and were not dispersed via the stack. Any potential emissions from the combustion of the solvent and pesticide wastes would not be measureable.