6 CCR 1007-3-8.47 - Basis and Purpose

These amendments to 6 CCR 1007-3, Part 261 are made pursuant to the authority granted to the Hazardous Waste Commission in § 25-15-302(2), C.R.S.

Amendment of Part 261 Appendix IX to Conditionally Delist F006 Hazardous Waste Generated by the Chemical Etching Process at the Wright & McGill Company located at 4245 East 46th Avenue in Denver. Colorado 80216

Appendix IX of Part 261 is being amended at this time to conditionally delist F006 hazardous waste generated by the chemical etching process at the Wright and McGill Company in Denver, Colorado. This delisting will allow the Wright and McGill Company to dispose of the waste generated from this process at a solid waste landfill that meets the requirements of the Colorado Solid Waste Regulations 6 CCR 1007-2, provided it complies with the conditions of the delisting.

On November 20, 2001, The Hazardous Waste Commission ("Commission") tentatively approved Wright & McGill's petition to delist F006 hazardous waste generated by the chemical etching process at the Wright & McGill Company located at 4245 East 46th Avenue in Denver, Colorado 80216. Pursuant to the provisions of § 25-15-302(2), C.R.S. and 6 CCR 1007-3, § 260.20(c), a public notice of the tentative decision to approve the delisting was published in the Colorado Register for written public comment. The public comment period closed on January 10, 2002. No comments were received. The tentative decision becomes the final decision as of February 25, 2002, and the delisting will become effective 20 days after publication in the Code of Colorado Regulations ("CCR") at 6 CCR 1007-3.

The Wright and McGill Company operates a manufacturing facility in Denver, Colorado for the production of fishhooks. One of the metal finishing operations conducted by the company is chemical etching. Wastewater that is generated from this operation is treated on-site to remove heavy metals and generates a wastewater treatment sludge that is classified as a F006 listed hazardous waste. The F006 hazardous waste listing in § 261.31 describes wastewater treatment sludge that is generated from electroplating operations. Electroplating has been defined by the EPA to include chemical etching.

The basis for each hazardous waste listing is described in Appendix VII of Part 261. Each listing is based on hazardous constituents that are generally contained in wastes described by the listing. The hazardous constituents that formed the basis for the F006 listing include hexavalent chromium, nickel, and cyanide (complexed).

Wastewater from the chemical etching process is transferred to the wastewater treatment unit for treatment. The wastewater enters the west treatment tank for metal precipitation using sodium hydrosulfide, anionic polymer, and sodium hydroxide. Following the treatment process, the liquid is decanted and the sludge is conveyed to a microfiltration system. The microfilters have an absolute filtration size of 10.0 microns. The sludge is then pumped through a filter press forming the F006 sludge.

Analytical sampling of the F006 sludge was conducted prior to the submittal of the delisting petition. The chemical etching process does not significantly change on a day-to-day basis, and the collected samples adequately represented the waste in question. The Hazardous Materials and Waste Management Division at the Colorado Department of Public Health and Environment (the Division), evaluated the sampling results and the request for petitioning of the waste in accordance with § 260.22. This evaluation was provided to the Commission.

The results of the waste sampling indicate that the waste did not contain detectable concentrations of hexavalent chromium or complexed cyanide. The results of the analysis did indicate that the waste contained detectable concentrations of cadmium and nickel. However, based on health-based risk assessment calculations derived using the general assumptions outlined in the Division's current risk assessment policy, the waste did not contain concentrations of these constituents at levels which would be considered harmful to human health or the environment.

Analytical sampling of the waste also indicated that the waste contained detectable concentrations of barium, trivalent chromium, and lead. Based on health based risk assessment calculations and average background soil conditions, the Division determined that the waste did not contain concentrations of those metals at levels which would be considered harmful to human health or the environment.

The potential for constituents in the waste to leach out and contaminate groundwater was evaluated by the Division using TCLP analytical tests that measure the maximum potential for constituents to be released from the waste. The results of the TCLP analysis indicated that arsenic, cadmium, hexavalent chromium, lead, mercury, selenium, and silver do not show any chemical potential to leach out of the waste. Additionally, barium and nickel showed only a small potential for those metals to leach from the waste. However, the Wright and McGill Company has indicated that all delisted sludge would be disposed in a solid waste landfill. Disposal in a solid waste landfill would ensure protection of human health and the environment from any metals contained in leachate that might migrate from the waste. Further, the results of the waste sampling indicated that the waste sludge does not contain any organic constituents. Consideration of the potential health effects caused by exposure to organic constituents was therefore not considered in evaluating the petition by the Division.

This delisting is being granted under conditions that specify disposal, record keeping, and storage requirements for the delisted sludge. Conditional delisting of the waste also prohibits any major changes to the chemical etching or wastewater treatment process without prior notification, evaluation, and approval by the Division.

This delisting does not apply to waste that demonstrates a "significant change" as defined in Delisting #005 in Part 261, Appendix IX-Wastes Excluded Under § 260.20 and § 260.22(d), or if any of the conditions specified in Part 261, Appendix IX for this delisting are not met. Should either of these occur, the waste is and must be managed as a hazardous waste. While the Division has approved a conditional delisting for this specific waste at this specific site, the findings and criteria associated with the approval are unique. Other petitions for delisting, even if similar in material or use, will be reviewed by the Division on a case-by-case basis.

Statement of Basis and Purpose - Rulemaking Hearing of April 16, 2002


6 CCR 1007-3-8.47
37 CR 24, December 25, 2014, effective 3/2/2015 38 CR 11, June 10, 2015, effective 6/30/2015 39 CR 05, March 10, 2016, effective 3/30/2016 39 CR 11, June 10, 2016, effective 6/30/2016 40 CR 06, March 25, 2017, effective 4/14/2017 40 CR 11, June 10, 2017, effective 6/30/2017 40 CR 21, November 10, 2017, effective 11/30/2017 41 CR 06, March 25, 2018, effective 4/14/2018 41 CR 11, June 10, 2018, effective 6/30/2018 41 CR 24, December 25, 2018, effective 1/14/2019 42 CR 06, March 25, 2019, effective 4/14/2019 42 CR 06, March 25, 2019, effective 5/30/2019 42 CR 11, June 10, 2019, effective 6/30/2019 43 CR 12, June 25, 2020, effective 7/15/2020 44 CR 06, March 25, 2021, effective 4/14/2021 44 CR 11, June 10, 2021, effective 6/30/2021 44 CR 24, December 25, 2021, effective 1/14/2022 45 CR 11, June 10, 2022, effective 6/30/2022 45 CR 17, September 10, 2022, effective 9/10/2022 45 CR 17, September 10, 2022, effective 9/30/2022 45 CR 23, December 10, 2022, effective 1/30/2023

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