Frequently Asked Questions

1. General Remediation Project Questions

The remediation is occurring now after years of planning, coordinating, and permitting with the Illinois Emergency Management Agency (IEMA).  When IEMA first issued the City’s radioactive material license in 2015, they triggered the need for the removal of the radioactive material. Before progressing to the removal phase, the remediation plan (also referred to as the decommissioning plan), required IEMA approval. This approval was received from IEMA in February 2021.

Construction activities are expected to begin in Spring 2022 and to be completed by the end of 2022.

Although certain activities may begin earlier, every effort will be made to conduct significant noise-generating activities between 8 am to 8 pm.   While large earth-moving equipment will be used, this project does not involve high noise generation from demolition activities such as building tear downs.   Some concrete and asphalt from within the excavation footprint will be removed as the excavation progresses.  The concrete and asphalt will be broken down with a jack hammer or hydraulic breaker attachment to an excavator.

The remediation is being conducted by F.H.Paschen. F.H. Paschen has retained Arcadis, Tecnica Environmental Services, and Griffin Dewatering to assist with the environmental aspects, earthwork, and dewatering and groundwater treatment for the project, respectively. Tecnica is a City of Chicago minority-owned business.  

The Department of Assets, Information and Services (AIS) with City of Chicago prepared construction bid documents to procure a remediation contractor.  The City advertised the bid in late fall 2020. The bid documents identify the health and safety, related project experience, and radiological licensing requirements that contractors must have to perform the project. Prior to the award, the City conducted a vetting process to determine if the selected Contractor meets City requirements and has not violated any City or sister agency policy, codes, state, federal, or local laws, rules or regulations and have not been subject to any debarment, suspension or other disciplinary action by any government agency.  

The site is contaminated with Radium-226, Uranium and Thorium-230.  IEMA set the site-specific soil clean-up levels in the City’s radioactive material license, which are provided below.

  • Radium-226 - 5.9 picocuries per gram (pCi/g)
  • Total uranium (U-234, U-235, and U-238) – 22 pCi/g to a depth of 5 meters (approx. 16 feet) and 52 pCi/g below a depth of 5 meters
  • Thorium-230 – 5.5 pCi/g

These clean-up levels factor in the presence of background concentrations as radium, uranium, and thorium are all naturally occurring elements and are based on IEMA, US Environmental Protection Agency (USEPA) and/or Nuclear Regulatory Commission guidance. 

The excavated area will be backfilled with clean stone or soil and the site will remain fenced off until redevelopment occurs.  Although the radiological contamination associated with Carnotite will have been addressed, other portions of the site including the green space still contain more traditional contaminants typical of urban settings, including lead and polynuclear aromatics (PNAs). This contamination will be addressed during site redevelopment.

Utilities in the excavation area have already been abandoned and will not be affected.   The excavation will continue through the winter season.

Prior to the start of construction, AIS will work closely with the Department of Streets and Sanitation and F.H. Paschen to identify potential rodent issues that may be caused by the disturbance from the excavation.  The identified rodent issues will be addressed with a Rodent Control Program, with an emphasis on protecting adjacent private property.  


2. Communication and Outreach

Prior to the start of construction, the City held a community meeting on June 1, 2021. The City will provide regular progress updates to the project website (www.chicago.gov/carnotite) during construction. These updates will include all air monitoring results and excavation progress.  In addition, the City is continually updating the mailing list for the project to ensure area residents and businesses are informed about community meetings and other updates. 

The City is providing a live video feed from an on-site video camera on the Carnotite website during site remediation.  

Throughout the remediation, the City will continue to answer questions through email (AIS_EHS_Notifications@cityofchicago.org) and its outreach telephone number (312-744-0500).  Residents without computer or internet access may request information including dust monitoring data be mailed to them by calling the outreach telephone number listed above. 

On November 13, 2020, AIS held a virtual meet and greet for MBE contractors to present their company qualifications to other non-MBEs.  A significant portion of the work is not available to MBEs due to the specific technical requirements of the work.  However, the site remediation contractor will hold a minimum of two job fairs to discuss the types of subcontracting work available for this project.  The site remediation contractor will also work closely with community organizations and the Alderman’s office to increase hiring opportunities for community members. While the City cannot direct the contractor in hiring procedures, they can work with the contractor to meet with the Alderman’s office to explore community hiring options.

F.H. Paschen will be holding a virtual job fair through Microsoft Teams on July 28, 2021 from 11:00 a.m. to 12:30 p.m.  A second job fair will be held in December 2021 or early 2022.  F.H. Paschen will be posting information on their social media accounts as well as sending flyers for distribution through Alderman Sophia King’s office and F.H. Paschen’s Workforce Partners.

Cook County is the property tax collection agency for homeowners in the City of Chicago.  The City of Chicago is not able to offer tax relief or incentives.  The remediation project provides removal of radioactive soil followed by a large development.  This improvement may result in increased property values in the area around the site. AIS has asked the Cook County Assessor’s Office to review this question along with information about the remediation project.  The FAQs will be updated when the Assessor’s office provides information regarding this question.

Remediation documents are available for viewing on the Carnotite remediation project website. Hard copies of reports can also be viewed and copied at the Chicago Public Library’s King Branch (3436 S. King Drive, 312-747-7543) during their regular business hours. The following documents are currently available at the King Branch:


3. Transportation and Access to Area Facilities

Two pedestrian walkways  provide access to the station, one from the north (26th Street) and one from south (Vernon Avenue/Ellis Avenue). On July 26, 2021, the north walkway was permanently closed.  The station is now accessible only from the south walkway. Prior to closure, pedestrian wayfinding signage was installed. These walkways are depicted in the Project Fact Sheet.

During construction, it is expected that trucks will enter and leave the site at 27th Street and Ellis Avenue and travel through the former Michael Reese Hospital site via S Cottage Grove Ave or S Lake Park Ave to access Lake Shore Drive from 31st Street. Flaggers and barriers will be provided at truck crossings to provide pedestrians with safe access to the Metra Station from the south walkway. Trucks will be decontaminated, run through a wheel wash system, and prior to leaving the site.

It is expected that one lane is always open on the 31st bridge to accommodate truck traffic. However, if the 31st Street bridge is under construction and cannot accommodate trucks, the alternative route could include 31st Street west to Dr. Martin Luther King Jr. Drive north to Interstate 55.

Our current plan (pending IEMA approval) is to transport and dispose a majority of the radioactive waste at the Waste Control Specialists (WCS) radioactive waste licensed landfill in Texas.  The waste will be placed in specially constructed radioactive waste bags (IP-1 bags) that will be packaged and sealed onsite before off-site transportation. An example of an IP-1 bag from another radioactive waste remediation site in Illinois is shown in this photograph. 

The bags will be stored in a protected area until they are ready for loading and transport by trucks.  The sealed bags will be secured on trucks and transported to railcars at an off-site intermodal yard to WCS in Texas for disposal.   Non-radioactive waste will be transported in tarped trucks to a local landfill. 

Each truck will pass through an automated wheel wash and be subject to thorough inspection by the on-site transportation and disposal coordinator prior to leaving the site to ensure no loose soil is adhering to the truck.  If spills occur, the contractor will clean up off-site spills or dirt tracked onto City rights-of-way or streets within an hour of notification of the spill.   In addition, significant spills while transporting the material will be cleaned up by the transportation company. 

IP-2 bag - radioactive waste bags


4. Safety and Monitoring Procedures

All personnel on the site will be adhering to health and safety plans approved by the Illinois Emergency Management Agency.  Site safety briefings will occur every day work is being conducted at the site.  As needed, additional meetings will be held to immediately address safety concerns (unsafe acts, near misses, stop work condition) or a change in scope.  Weekly progress meetings will be conducted to facilitate communication of short-term and long-term planning, including work sequencing and associated staffing and safety requirements.

All personnel have the authority to “STOP WORK” if they see an unsafe act or condition.  Work conditions will be discussed in safety briefing immediately after stopping work.  All necessary changes will be made before resuming work to ensure safe working conditions.

Additional precautions include dust monitoring in the work area and site perimeter and radiological air particulates along the site perimeter. Please refer to FAQs 4D, 4E, and 4F for additional details on these dust mitigation and air monitoring efforts.

Area pedestrians will be protected through extensive site signage, construction flaggers, barricades and construction fencing. 

No.  In 1979, the State of Illinois Department of Health, Division of Radiological Health (a predecessor to the Illinois Emergency Management Agency (IEMA), in cooperation with the U.S. Environmental Protection Agency (EPA), conducted a radiological surface survey of the northern portion of the Michael Reese property near 26th Street, and concluded that the contamination did not pose an immediate health hazard but should be removed prior to any future construction. Most impacted material is limited to the top 5 feet below ground surface (bgs) but extends to approximately 14 feet bgs within one area in the northwest portion of the Site.

IEMA is the regulatory agency that will be overseeing the remediation activities at this site. The remediation work is being completed under an IEMA-issued decommissioning license and in accordance with an IEMA-approved decommissioning plan. Prior to starting work, the contractor’s work plans will be submitted to AIS and IEMA for review and approval. IEMA will conduct routine site inspections for the duration of the project.

The City (department of AIS) will be managing the remediation project and has also retained an independent remediation oversight and construction management consultant to oversee work performed by the remediation contractor.  AIS’ oversight representatives, including a radiation safety officer, have successfully conducted radiation-contaminated soil remediation and monitoring at multiple sites throughout the U.S. Examples of this experience include three of the Ottawa, Illinois, Radiation Areas and many sublocations associated with the Lindsay Light Superfund sites. AIS’ oversight representatives are applying that experience to the Carnotite site. Depending on the number of activities and work each day during construction, 2 to 4 oversight personnel will be on site monitoring activities.   

These oversight services will include providing a Radiation Safety Officer (RSO) to monitor for radiation safety, providing an on-site presence for all license-related activities, monitoring for the remediation contractor’s compliance with bid document including dust control requirements, performing air monitoring, conducting field surveys and sampling, and preparing weekly progress reports. The City’s RSO will have the authority to stop all work activities if radiation monitoring detects concentrations above action levels.

The primary measure currently proposed (pending IEMA approval) to control dust exposure is to eliminate or minimize operational activities that contribute to dust generation, such as on-site staging and blending of soil. In the proposed approach, the contractor will direct-load a majority of the waste into radioactive waste bags (IP-1 bags) that will be packaged and sealed onsite before off-site transportation to the Waste Control Specialists (WCS) radioactive waste licensed landfill in Texas.

Based on experience at similar sites, other sources of dust generation are from on-site truck and vehicle traffic. The contractor will be required to implement dust suppression measures to minimize dust generation from activities such as excavation, stockpiling, loading, and on-site truck traffic. The contractor will be required to cease dust-generating activities during periods of adverse weather (e.g., sustained winds exceeding 20 miles per hour averaged over a 10-minute period). Any time visible dust is observed at the site, the contractor will be required to take actions within 20 minutes to stop the generation of visible dust. Keeping a clean haul roadway, misting water on site roadways as needed and routing trucks through the wheel wash prior to leaving the site will minimize dust generation at the site.  General dust control actions may include water misting, covers, crusting agent, or equivalent as well as regulating equipment speeds and limiting traffic volume.

A third measure will include use of shade cloth on perimeter fencing, which is 8 to 10 feet in height, and covering inactive soil stockpiles with plastic sheeting, which will further assist in minimizing dust levels at the site.

All of the measures discussed above have been used at multiple remediation sites and shown to be effective in controlling dust generation at sites.  For example, Tetra Tech regularly uses these dust control measures at the Ottawa Radiation site in Ottawa, Illinois, to control dust generation during remediation.  The contractor’s construction plans and procedures for dust control are currently being prepared.  Additional details will be shared once approved by IEMA.

Dust monitoring requirements will be included in the Health and Safety Plan/Radiation Protection Plan (HASP/RPP) and Field Sampling Plan prepared for the project that will be reviewed and approved by IEMA prior to starting work.   These plans specify a dust action level for public exposure at the site perimeter based on the U.S. Environmental Protection Agency National Ambient Air Quality Standards for particulate pollution from Title 40 of the Code of Federal Regulations (CFR) Part 50.6, which are set to be protective of human health.  The site-specific action level is 150 micrograms per cubic meter (μg/m3) per 24 hours based on respirable particles, with diameters that are generally 10 micrometers and smaller. 

However, additional separate radiological monitoring is required as dust monitoring data alone cannot be used to determine radiation concentrations. This is because dust potentially generated from the site will not always contain radioactive particulates and a correlation is not possible. Please refer to FAQs 4F for additional details on the required separate radiological monitoring.

The site-specific dust action level of 150 μg/m3 is utilized as an early warning sign of dust control issues.  During construction, dust suppression measures such as water misting will be actively applied to minimize dust generation. However, if site action levels are exceeded, work will be stopped, and dust suppression measures will continue until dust levels are below the established action level.

Dust monitors will be run continuously along the site perimeter (fence line monitoring), including during non-working hours. Monitoring will be reviewed in real time and alarms are set to notify the oversight contractor if the site action level is exceeded.  Each evening, the dust monitoring results for the previous working hours will be downloaded and converted into a format that is easy to understand and posted on the project website.

At a minimum, the City’s remediation oversight consultant will perform dust monitoring activities in two areas 1) within the active work area, and 2) along the site perimeter. The details on dust monitoring performed by the oversight consultant in the work area and at the fence line are presented below.

  • Work area monitoring- conducted by use of continuous, real-time, direct-read particulate monitors capable of measuring respirable dust particles. The dust monitors will be placed on tripods to sample air at the breathing zone. They will be run continuously each day during excavation and soil management activities and be relocated within the work area as necessary to collect the most representative sample near work activities.
  • Site perimeter monitoring– conducted by use of four continuous, real-time, direct-read dust monitors deployed at the site perimeter and placed approximately in cardinal directions. Locations of perimeter air monitoring stations may be adjusted as necessary to ensure at least one dust monitor is upwind of the site and one dust monitor is downwind of excavation and soil management activities at the site. The dust monitors will be used in conjunction with a telemetry system to continuously record and monitor dust levels in breathing zone ambient air at the site perimeter. 

 

A circus tent (sprung structure) is a large undertaking and is typically used for environmental remediation for soil containing volatile contaminants like benzene.  These contaminants cannot be seen and are more difficult to control.  Dust from excavations, including dust with radioactive materials, is not volatile and may be effectively controlled through water spraying and stopping work under adverse wind conditions.

Tarps over an excavation will be difficult to secure and may become airborne and potentially migrate offsite, which would pose hazards to the community. Please refer to 4D for dust control measures that will be implemented throughout construction.

Regulatory agencies will be performing inspections on a routine basis.  As the lead regulatory agency, IEMA will conduct site inspections throughout the duration of the project to monitor compliance with all application regulations including dust control. If compliance issues are identified, IEMA may issue a notice of violation and/or require work stoppage until the issues are resolved to their satisfaction.

The Chicago Department of Public Health (CDPH) will also conduct site inspections for compliance with local regulations, including the City’s Construction Site Cleanliness Ordinance (Section 13-32-125).  AIS will work with CDPH to ensure that regular site inspections are conducted. 

Please refer to FAQs 4E and 4F for additional monitoring activities that will be conducted during remediation.

Air particulate monitoring and direct gamma radiation measurements at the site perimeter will be used to demonstrate that radiation levels are well below the public dose limits set by IEMA.  These dose limits and methods for demonstrating compliance can be found in 32 Illinois Administrative Code (IAC) 340.310 and 320.  The site radioactive materials license requires that these measurements and calculations be submitted quarterly to the regulators for review and approval.  The results will be posted on the Carnotite website upon regulatory approval.

Under the site radioactive material license, IEMA set radium, uranium, and thorium air particulate action levels for site perimeter monitoring equal to the Nuclear Regulatory Commission air effluent concentrations listed in 10 CFR 20, Appendix B, Table 2.  These limits are 9.00 E-13 microcuries per milliliter (µCi/ml) for radium-226, 9.00 E-14 µCi/ml for uranium, and 2.00 E-14 µCi/ml for thorium-230.  These action levels are equivalent to the concentration that, if inhaled or ingested continuously over the course of a year, would produce a total effective dose equivalent of 50 millirem (mRem), which is approximately equivalent to 5 chest x-rays per U.S. Nuclear Regulatory Commission guidance (link is provided below).  This action level is conservative because the IEMA required annual public total effective dose limit in 32 IAC 340.310 is 100 mRem.  The conservative air particulate action levels will ensure that the public is not exposed to radiation levels in excess of dose limits set by IEMA to ensure public health and safety. 

For general information regarding radiation, including natural radiation sources, see the following information from the EPA and NRC:

While dust is not expected to be a problem for local residents during remediation, there are a number of ways everyone can reduce their exposure to regularly-occurring dust in the area and make their homes healthier.

  • Regularly clean your floors and wipe down any counters and surfaces to keep them free of dust, since dust may settle on floors and surfaces in your home.
  • Make sure all family members remove their shoes before entering your home to help keep dust outside.
  • You may wish to keep windows closed on very dry and windy days when dust is visible.

Within the City of Chicago there are many potential uncontrolled sources of non-radiologically contaminated dust.  Radiological air particulate monitoring at the site perimeter will be conducted continuously to demonstrate radiation levels are well below the public dose limits set by IEMA. 

Site personnel will check daily weather forecast for storm events. If a storm with winds exceeding 20 mph or rainfall exceeding 0.5 inch rain event is forecasted, site personnel will verbally notify all personnel, contractors, and visitors of the pending storm. The following actions will be implemented prior to a storm event to minimize any adverse impacts:

  • Actions to minimize impact to Air Quality:
    • Soil tackifier is applied regularly in the excavation as conditions warrant, prior to a hiatus in excavation or a storm event. The tackifier forms a sticky coating on the surface of soil and prevents soil from getting caught up in the air during high wind conditions.
    • The handling of loose soil will stop when rainfall exceeds 0.25-inches in one hour or sustained wind speeds exceed 20 miles per hour (mph).
    • The perimeter fence fabric is inspected daily including before a storm. 
  • Actions to minimize Impacts to stormwater runoffs:
    • Erosion controls (silt fence, protection of stormwater inlets etc.) are inspected weekly including before a storm event.
    • Cover stockpiles of loose materials with plastic and inspect daily including before a storm event.

The following actions will be taken to minimize impacts after a storm (as soon as it is safe to do so):

  • Check condition of tackifier and reapply where needed.
  • Inspect the perimeter fence fabric and repair when contractors and materials become available.
  • Inspect erosion controls and repair if needed.
  • Inspect stockpile covers and restore if needed

 In addition to the contractor, AIS’ consultant and subconsultant also perform daily site inspections to check on air monitoring stations, BMPs, groundwater treatment system, equipment, and other general site items for storm preparedness.


5. Drinking Water Protection and Stormwater Protection

The Contractor will be required to implement a Stormwater Pollution Prevention Plan (SWPPP). The SWPPP will include soil and erosion control measures within the work area to prevent stormwater runoff from coming into contact with disturbed areas that may be contaminated. Control measures will include silt fencing, stormwater drain inlet protection, and berms and coverings for any soil stockpiles.  Stormwater that comes into contact with excavation areas will be either treated onsite in a treatment system prior to discharge to the sanitary sewer as permitted by the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) or containerized and disposed of off-site at an approved disposal facility.

Yes. The water supply mains providing drinking water from Lake Michigan are located west of the contaminated areas at the site and do not cross the contaminated areas. Water mains are also under pressure. Any cracks in the pipes will result in water exiting the pipe. The pressure inside the pipe also prevents surrounding materials (soil or groundwater) from infiltrating the pipe.


6. General Radiological Questions

This is a difficult comparison to make since the scenarios are vastly different with different isotopes, dispersion, etc.  However, an attempt to compare them in scale based on the amount of radioactivity emitted into the environment has been made.  Although this is not a reasonable possibility at Carnotite, for discussion purposes assume that the maximum observed concentration of each isotope among all soil samples (5,239 pCi/g total concentration of uranium + radium + thorium) is present in all 17,385 cubic yards of material that is planned to be excavated and 100% of this material is released into the environment. In this scenario, approximately 91 Curies (Ci) would be emitted from contamination at the Carnotite site (see below calculation).

  • 17,385 Cubic Yards of Material to be Excavated x 2,200 lbs. / yd3 = 3.8247 x 107 lbs. of material
  • 3.8247 x 107 lbs. of material x 453.592 grams/lb = 1.7349 x 1010 total grams to be excavated

Assume that the entire site is the MAX concentration (for each isotope), all 17,385 yards is 5,239 pCi/g total concentration (uranium + radium + thorium).

  • 1.7329 x 1010 grams x 5,239 pCi/g = 9.0787 x 1013 total pCi at the site.
  • 9.0787 x 1013 pCi x 1 Ci/1 x1012 pCi = 90.7866 Curies total at the site.

This is absolute worst case, but in no way reflected by the 150+ soil samples analyzed during characterization. In comparison, Chernobyl Activity Released into Environment is approximately 5200 Petabecquerels (PBq) or 140,540,400 Ci and Fukushima Activity Released into Environment is approximately 770 PBq or 20,810,790 Ci.

In summary, the activity released into the environment for the Carnotite site and the two nuclear disasters are:

  • Carnotite ~ 91 Ci
  • Chernobyl ~ 140,000,000 Ci, and
  • Fukushima ~ 20,000,000 Ci

As shown above, the activity release from the Carnotite site (with extremely conservative assumptions) is still at least six orders of magnitude lower than Chernobyl or Fukushima disasters.

Presented in the below table are concentrations of uranium, radium, and thorium in various innocuous products as well as another radiologically contaminated site. The maximum concentration at the Carnotite site for the radionuclides are approximately five times to two orders of magnitude lower than the low-level radioactive waste acceptance criteria at the Waste Control Specialist’s landfill in Andrews, Texas where the Carnotite radiological waste will be disposed.

 

 

Uranium

Radium

Thorium

Description

pCi/g

pCi/g

pCi/g

Soil - Background

0.8

0.9

2

Cat Litter

4

N/A

3

Lawn Fertilizer 1

22-140

0.7-24

5.4-130

US Department of Transportation Exempt Concentrations 2

270

270

27

Carnotite Site 3

3,670

1,124

445

Kerr-McGee West Chicago Rare Earths Facility 4

3,426

31,500

11,050

Waste Control Specialists Landfill radionuclide waste acceptance criteria for low-level radioactive material 5

300,000

5,000

25,800

1 NCRP Report No. 95 Radiation Exposure of the US Population from Consumer Products and Miscellaneous Sources

2 49 CFR 173.436 Exempt material activity concentrations and exempt consignment activity limits for radionuclides.  Soil containing radionuclide concentrations below these levels are not considered low-level radioactive waste per DOT regulations. At the Carnotite site, only 17 of approximately 170 soil samples (or 10%) exceed the DOT exempt concentrations and will be shipped as low level radioactive waste (see Carnotite soil analytical results presented in the Decommissioning Plan, Table 3, as referenced below).

3 Decommissioning Plan Rev.5, Former Carnotite Reduction Company Site, Table 3 - Soil Analytical Results Summary

4 USNRC NUREG-0904, Supplement 1, Volume 1 ; Supplement to the Final Environmental Statement related to the decommissioning of the Rare Earths Facility, West Chicago, Illinois; Table 2.3.

5 Waste Control Specialists RCRA Subtitle C Landfill, Andrews, Texas

Concentrations of radioactive material are important, but there are many factors involved in determining risk. Risk is based on dose.  Dose is the measurement of interaction of ionizing radiation in the human body and the biological effects of those interactions. Regulatory agencies place dose limits on occupational exposure and public exposure. Compliance with those dose limits is performed through surveys and sampling. The following NRC document explains risk related to radiological dose. 

1996/02/29-Regulatory Guide 8.29 (Draft issued as DG-8012) Revision 1 Instruction Concerning Risks From Occupational Radiation Exposure (nrc.gov)

Before estimating the magnitude of the risk, it is important to understand how risk is determined. As discussed in the FAQ titled “6c. How is radiological risk determined?”, risk is based on dose. Dose is the measurement of interaction of ionizing radiation in the human body and the biological effects of those interactions. Regulatory agencies place dose limits on occupational exposure and public exposure. Compliance with those dose limits is performed through surveys and sampling. For the Carnotite project, the public dose limit is set by the Illinois Emergency Management Agency (IEMA) and is 100 mrem/year (0.1 rem). As described in U.S. Nuclear Regulatory Commission (NRC) Regulatory Guide 8.29, “Instruction Concerning Risks from Occupational Radiation Exposure” in Item 8 on page 8.29-7 (https://www.nrc.gov/docs/ML0037/ML003739438.pdf), this dose would result in a 4 in 100,000 chance (based on the linear model) of developing a fatal cancer using the risk value determined by NRC.

Approximately one in five adults normally will die from cancer from all possible causes such as smoking, food, alcohol, drugs, air pollutants, natural background radiation, and inherited traits. Thus, in any group of 10,000 workers, NRC estimates that about 2,000 (20%) will die from cancer without any occupational radiation exposure. This means that a 100 mrem (0.1 rem) dose (public dose limit) may increase an individual’s chances of dying from cancer from 20 percent to 20.004 percent (based on the linear model).

 

The Denver Radiation Superfund Site is relevant, but on a much larger scale. This site consists of 65 different properties in the city of Denver in similar residential and commercial area. The importance is that it is nearly identical to the Carnotite Site, where they processed the same Carnotite ore in the same manner, which resulted in the same uranium, radium, and thorium contamination – but much more widespread.

 

The following report details the cleanup operations that took place. There are vast amounts of publicly available information about the regulatory oversight and radiological monitoring that took place there from 1979 to 2014. We are using similar procedures and monitoring that has been successfully deployed in the past to ensure public health and safety and minimize cross-contamination.

 

CompleteRadiumReport2014.pdf (denvergov.org)