On September 21, 2022, the Denver Department of Public Health and Environment (DDPHE) contacted EPA about a residential property with various unknown chemical containers, small radiological sources, and other unknown chemical hazards. DDPHE requested EPA assistance with assessment and management of the hazardous substances in the residential home.

The hazardous substances were in a residential duplex home. A singe wall separated this residence from the neighbors. The house is in a residential neighborhood surrounded by single family homes. The hazardous substances were throughout the residence stored with food and household items.

The house has been condemned and deemed un-inhabitable by DDPHE for being an imminent hazard to public or environmental health and unfit and unsafe for human habitation or presence. DDPHE evicted the occupant and evacuated the pets. The property owner that purchased the radiological sources and chemicals had been moved to assisted living a few months prior.

An access agreement was signed by the Site owner. EPA met with DDPHE on-site. DDPHE conducted a background briefing and we performed a quick walk-through of property.

EPA performed monitoring with Ludlum 193 radiation detector, Multirae air monitor, and Jerome mercury vapor monitor. Radiation sources were traced to a closet near the back door. Multiple hazardous substances were seen throughout the house. The chemicals were mixed with everyday household items and food. The chemicals were improperly stored with flammables, oxidizers, and reactive chemicals stored together that could be a fire hazard.

As a precaution, EPA received an access agreement from the duplex neighbor and conducted similar monitoring. The readings were not elevated.

EPA decided that this Site needed to be addressed as an emergency response due to the radionuclides and types of hazardous substances improperly stored in the house. Since the house had been condemned these chemicals were considered abandoned. DDPHE turned over control of the property to the EPA until EPA work has been completed. The EPA installed new locks to prevent unauthorized entry and to protect the public.

Obtain access to site.

Assess the site to ensure area is safe to enter and work.

Remove, identify, segregate radiation sources and store in a safe manor. Prepare radiation sources for transportation and disposal.

Remove, identify, segregate and store chemicals found on site. Prepare chemicals for transportation and disposal.

Coordinate work with DDPHE and other stakeholders.

Inform neighbors, public and DDPHE of work activities at site.

9/21/22

Access agreement was signed by owner.

The house has been condemned and deemed un-inhabitable by Denver Department of Public Health and Environment for being an imminent hazard to public or environmental health and unfit and unsafe for human habitation or presence. The city evicted the owners and evacuated the pets.

The City or property owner called in the Denver bomb squid prior to EPA arrival and the bomb squad cleared the property. EPA was not given the details for the bomb squad deployment but apparently the property owner self reported something that caused this action.

EPA met with City of Denver, Public Health and Environment office, to walk through property and get background information on the site. The City performed a preliminary assessment and performed some air and radiation monitoring prior to EPA arrival.

START mobilized to site and began assessing site. Performed walk through with Ludlum 193 radiation detector, Multirae air monitor, and Jerome mercury vapor monitor. Radiation sources were detected in a closet near the back door. Multiple hazardous chemicals were seen throughout the house. The chemicals are mixed with everyday household items as well as next to food items.

EPA received an access agreement from the neighbor’s that shared a wall with the site. EPA and contractors performed walk through with Ludlum 193 radiation detector, Multirae air monitor, and Jerome mercury vapor monitor. Nothing above background was detected except for radiation. Background readings varied between 20-35 micro-Rem/hr (uR/hr) and radiation results in residence were around 35 uR/hr on the high side of the background readings but not high enough to considering relocation of residence.

The City turned over control of the property to the EPA until EPA work has been completed. The property had new locks installed to prevent unauthorized entry to protect the public.

Website created to inform public and stakeholders at response.epa.gov/WolffStreetChemicals.

9/22/22

ERRS mobilized to site with 2 pickup trucks and a response trailer.

ERRS started clearing each room and removing any hazardous chemicals as they found them. A closet full of radiological items was identified and each items was removed and tested for radiation and identification.

START continued to monitor air for VOC, LEL HCN H2S CO O2 LEL SO2 inside the home and outside where crews are working.

START has started testing the radioactive material using the SAM 950 that can detect the amount of radiation and the type of radioactive material.

START has started performing hazardous classification and categorization on the hazardous chemicals to ensure it can be disposed of properly. 

Talked with City of Denver, Public Health and Environment office to discuss what items could be left behind and what needed to be removed that were not hazardous chemicals or radiological but still posed a health and environmental issues such as medications and other items.

9/23/22

Performing air monitoring inside home and near work areas to ensure worker and public safety. VOC, LEL HCN H2S CO O2 LEL SO2

ERRS reports completing the inspection and removal of all chemicals in the house.

START continued to monitor air for VOC, LEL HCN H2S CO O2 LEL SO2 inside the home and outside where crews are working.

START has continued testing the radioactive material using the SAM 950 that can detect the amount of radiation and the type of radioactive material.

START has continued performing hazardous classification and categorization on the hazardous chemicals to ensure it can be disposed of properly.

START begins to generate container inventory for all containers removed from the residence. Containers that were hazclass labeled as HCO-0XX, and all containers screened for radiation were labeled as RCO-0XX.

ERRS continue to segregate each chemical into compatible containers, preparing for shipment and disposal of chemicals.

ERRS continues to segregate radiative materials into compatible containers.

For radioactive material, ERRS scheduled pick up and transport for 9/28/22 with a broker to take waste to US Ecology in Idaho for disposal.

Met with neighbor to update her on progress and to answer concerns.

Met with City of Denver, Public Health and Environment office, to update him on progress of work and walk through property.

9/24/22

Continued testing the radioactive material using the SAM 950 that can detect the amount of radiation and the type of radioactive material.

Continued performing hazardous classification and categorization on the hazardous chemicals to ensure it can be disposed of properly.

START completed identifying and reading radiological sources. START screened a total of 60 samples for radiation. Samples were divided into different isotopes for disposal. The main isotopes detected included In-111, Th-232, Ra-226 and Co-60. Sources that were screening just above background, 20-25uR/hr compared to background of 15 uR/hr, were grouped together as miscellaneous rad sources and placed in a blue 55- gal drum.

9/25/22

After reviewing the chemicals in the refrigerator and how unstable they were, EPA decided to call the bomb squad to dispose of the chemicals in the refrigerator. Bomb squad will be out on Monday or Tuesday to give them time to research the chemicals. 

START and ERRS completed hazardous classification and categorization of the hazardous chemicals. They completed segregating each chemical into compatible containers, preparing for shipment and disposal of chemicals.

START hazclassed and reviewed a total of 176 containers found within the residence. Substances varied greatly including elemental metals and various liquids (chemical and household hazardous waste), medication, acids, bases, variety of unlabeled powders, and glass ampoules of gas. A number of containers were not hazclassed due to health risks associated with the chemicals or because the container was sealed from the manufacturer.

START assisted ERRS in segregation of substances into DOT regulated waste streams. Waste streams included, oxidizers, peroxides, flammables liquids and solids, inorganic and organic acids and bases (both solid and liquid), radioactive, nonflammable and poisonous gases, biohazardous material, poison, combustible materials.

9/26/22

The Denver Bomb Squad reported that they would deploy to site on Tuesday. They are still doing research and waiting to hear back from the FBI chemist.

9/27/22

Denver Bomb Squad arrived at 0915. They packed the diethyl ether, ammonium perchlorate and dimethyl sulfoxide and put it in an explosive proof container on a trailer. They are taking it to their range to destroy.

9/28/22

Radiological material was analyzed, picked up and transported for disposal by Curie Environmental Services. 

Last sweep of residence found a couple more hazardous substances. They were identified, segregated and packaged for disposal.

EPA, START and ERRS demobilized from site.

Properly transport and dispose of radioactive waste.

Properly transport and dispose of hazardous substances.

Physical Hazards: Low cables above back yard that needs to be avoided. Tripping and falling hazards from the large amount of debris.

Various chemicals hazards that have to be handle properly with correct PPE.

Various radiation sources that needs to be handled properly with proper PPE.

Biological hazards that need to be address with proper PPE.

Explosion hazards:

After reviewing the chemicals in the refrigerator and how unstable they were, EPA decided to call the bomb squad to dispose of the chemicals in the refrigerator. Bomb squad will be out on Tuesday (9/27/22) to give them time to research the chemicals.