Screening is the DEQ Cleanup Section's initial evaluation of sites that have been added to the agency’s Environmental Cleanup Site Information system. (ECSI is DEQ’s electronic database of sites with known or suspected hazardous substance contamination.) DEQ adds sites to ECSI based on information from a variety of sources, including referrals from other programs, spills, complaints, and unsolicited reports, as well as from Site Assessment staff’s discovery of sites that may present significant threats to human health or the environment. Site screening is designed to:
- determine whether a release of a hazardous substance has occurred or could occur;
- determine whether site contamination poses or may pose a significant threat to human health or the environment;
- determine what further actions are needed at a site, and the priority for those actions;
- document Site Assessment’s decision-making process; and
- provide information for updating the ECSI database.
There are six general actions associated with a site screening, as explained below:
- Gather available site data. Site Assessment staff first review readily available information from internal DEQ files, U.S. Geological Survey topographical maps, and other agencies. Then, to obtain additional facility data, staff normally send an information request letter to the site owner or operator. Tailored to the site, this letter may request site investigation or cleanup reports not in DEQ files, information about disposal of hazardous substances used or generated at the facility, details on historic or current facility operations, and other related information.
- Evaluate site information; develop and document conclusions. Site Assessment’s standard screening write-up is called a Strategy Recommendation, which addresses site history and contamination issues, highlights likely pathways of exposure, presents DEQ’s recommendations for further action (if any- sometimes screenings result in no-further-action determinations), and lists references. For sites needing further actions, the Strategy Recommendation indicates the priority for those actions (see item #3 below). The Strategy Recommendation also presents a listing recommendation (see item #4 below).
- Assign a priority for further site action(s). Using DEQ’s Site Assessment Prioritization System, or SAPS, staff determine the priority – low, medium, or high – for further actions needed. SAPS integrates many features associated with the site, and gives a final "score" that Site Assessment staff use in assigning a site priority. The priority given depends on information, such as:
Make a listing recommendation (i.e., should the site be added to the Confirmed Release List or Inventory?). If a hazardous substance release has been documented, the site may qualify for the CRL. The site may also qualify for the Inventory, if a release has been documented and a PA or PA Equivalent has been completed. (See below for a discussion of PAs and PA Equivalents.) If a site is eligible for either the CRL or Inventory, state law obligates DEQ to pursue listing as a way to notify the public of contaminated sites. CRL or Inventory listing is not meant to assign cleanup liability to specific persons or companies.
Update ECSI. When the screening is final, Site Assessment staff update the ECSI database with information on site contamination issues, concentrations of hazardous substances in various media (if data is available), recommended further actions (including CRL/Inventory listing recommendations), and site priority. A primary objective of updating ECSI after a screening is to provide, for other DEQ staff and the general public, a concise and current summary of site issues and the human health or the environmental threats the site may pose.
Notify owner/operators of screening results and conclusions. To complete the screening, Site Assessment staff send a letter to responsible parties describing what further actions are needed and under what priority. This letter is often referred to as an "options letter," because it lays out several choices available to RPs. For low- or medium-priority sites, DEQ usually gives RPs three options: 1) pursue further action under DEQ’s Voluntary Cleanup Program; 2) implement further actions independently (i.e., without VCP oversight); or 3) take no action and wait for DEQ to take the next step. For high-priority sites (where risks to human health or the environment are considered imminent or substantial), DEQ may limit RPs’ options so that the agency retains more control over the nature and timing of remedial actions. A "no-further-action" letter is another possible outcome of a screening.
- manner of release and media affected by hazardous substances;
- approximate volume(s) of contaminated media at site;
- toxicity and water solubility of contaminant(s) of concern;
- groundwater depth and main uses of groundwater within 2 miles of the site;
- distance to the nearest recorded drinking water well;
- distance to surface water, and main uses of surface water within 2 miles of the site;
- permeability of surface and near-surface soils;
- main land uses within ½ mile of site;
- site’s proximity to defined Sensitive Environments [Oregon Administrative Rules 340-122-115]; and
- likelihood of human direct contact with hazardous substances.
Under state law (Oregon Revised Statute 465.245), DEQ conducts Preliminary Assessments at sites where hazardous substances may pose a significant threat to human health or the environment. Compared to a screening, the PA is a more formal and detailed investigation, designed to determine whether a site is releasing, has released, or could release hazardous substances to the environment, and whether a response action is required. For a PA, the investigator compiles available data about a site and its immediate vicinity. This includes site history and operations, information on potential sources of contamination, pathways for migration of contaminants, and receptors or targets potentially affected by the contamination. The PA Report summarizes data gathered about the site and makes recommendations for further action that are as specific as possible, given the facts available. While the PA identifies whether a site could endanger human health or the environment, it is not intended to fully characterize site contamination or to quantify the magnitude of site risks.
Following a PA, some sites require sampling to determine what further actions might be needed. In such cases, an additional investigative effort and report are called for: an Expanded PA.
- Brief description of current site operations.
- Size of site in acres.
- Number, type, location of buildings, hazardous substance/waste storage, disposal and treatment areas.
- Unique land or site features - sink holes, site situated in a gravel pit, etc.
- Adjacent land use – a description of structures and activities on property within 1,000 feet of contaminated or potentially contaminated area (agricultural, residential, industrial, etc.)
- Site security - fenced, 24-hour guard, locked/open gate, etc.?
- Site location map - The site location map should be a copy of a topographic map that indicates the location of the site in relation to the rest of the state. Specifically, the map should include the following: outline of site boundaries; site name; overland route to nearest surface water; surface water intakes (if applicable); nearest well; nearest residence; 2-mile surface water target distance limit (if possible); unique points of interest (e.g., Sensitive Environments); and adjacent land use.
- Site/facility map - The site map can either be a drawing made during the site visit, or a facility layout map supplied by the subject facility. It should include the following: site boundaries - fencing, gate location, or any structure that prohibits entrance; building locations, names, and functions, including interior/exterior process areas, chemical/waste storage/disposal areas, spill location, homes, well houses, etc.; sources of hazardous substances - both active, inactive, and historical; flow direction of on-site drainage; unique features; location of any wells on-site, including production, injection, abandoned, or monitoring wells; and storage tanks (above and below ground) - past and present locations.
Ownership and Operational History
- Ownership history - dates of ownership/operators, names, type (federal, private, state, etc.), leased, owned, etc., as far back as possible.
- Operating history - past and current practices, dates of operations, hazardous substances used, production processes, as far back as possible. As applicable, manufacturing, waste disposal, and storage process flow diagrams are helpful.
- Discussion of known or potential problem(s) - known or potential contaminants of concern; summary of existing analytical data; emergency or remedial actions that have occurred; pathways affected or of concern (groundwater, surface water, air, or direct contact); documented problems: drinking water, groundwater, or surface water contamination, documented releases, etc.; potential problems: (e.g., wastes dumped on-site, indicating possible groundwater contamination, but sample data is unavailable); unique problems potentially associated with contamination: e.g., an abnormally high death rate in cattle that drink from the creek downstream of site, high incidence of cancer among area residents, odor or strange color in well water, etc.
- Sample location map(s) - if applicable, this map will compile all past sampling events, using codes to distinguish between different sampling media and events. The codes should correspond to the table of analytical results found in the PA. More than one map may be needed to indicate locations. These maps are typically copies of the site/facility map and/or site location map, with sample locations added.
- Permits - type, issuing agency, dates of issue and expiration, compliance/noncompliance status, etc. For noncompliance: state date, nature, and corrective action(s) taken.
- Past inspections - inspecting party (DEQ, EPA, OSHA, owner/operator, etc.), inspection results, sample collection, analytical results, etc. Include table(s) of analytical results. This section includes not only official government inspections, but any inspection performed at the facility, such as by consultants on behalf of owner/operators or lending institutions.
- Summary of site visit - a brief summary of discussions and/or key observations made during the site visit.
This section covers past, present, known, and potential sources of hazardous substances at the site. These comprise areas with documented releases of hazardous substances, where there is a threat of release, or where hazardous substances have been stored or disposed of.
A source can mean any building, structure, installation, equipment, pipe or pipeline (including any pipe into a sewer or publicly owned treatment works), well, pit, pond, lagoon, impoundment, ditch, landfill, storage container, above-ground or underground storage tank, motor vehicle, or any area where a hazardous substance has been deposited, stored, disposed of, placed, or otherwise come to be located, and where a release has occurred or where there is a threat of a release.
This section includes areas where hazardous substances may be present but do not pose a threat of release to the environment. All areas where hazardous substances are handled should be listed.
Discussion of permitted or authorized releases belong in the PA’s Regulatory History section. A permitted or authorized release is a release from an active facility that is subject to and in substantial compliance with a current and legally enforceable permit issued by an authorized public agency [Oregon Administrative Rule 340-122-115]. Note that deposition, accumulation, or migration of substances resulting from an otherwise permitted or authorized release is excluded from the definition of a permitted or authorized release [OAR 340-122-073].
Where detailed information is not available, such deficiencies should be noted, and estimates used for source containment, size, and quantity/types of contaminants present. This section will also identify hazardous substances that have not been handled in the hazardous substance release areas listed above. Describe how the facility uses, treats, disposes of, or recycles these substances.
For each source, where a release or a threat of a release exists, describe:
- Name and location of source
- Type of source - landfill, surface impoundment, container, storage tank, contaminated soil, pile, etc. A landfill is an engineered hole in the ground into which hazardous substances have been disposed by backfilling or by contemporaneous soil deposition that covers wastes from view. A surface impoundment is a topographic depression, excavation, or diked area, formed from earthen materials (lined or unlined) and designed to hold wastes containing free liquids. Drums are portable containers that hold a standard 55-gallon volume of hazardous substances. Tanks and Non-Drum Containers are other portable or stationary devices used to contain accumulated wastes. A pile is any non-containerized, above-ground accumulation of solid, non-flowing wastes, including open dumps.
- Current use and length of use - active, inactive, documented clean-closed, undocumented clean-closed, frequency and dates of use, etc.
- Permits addressing source (if applicable).
- Type and condition of containment - Is the source lined or unlined? Is it breached or unbreached, is there a cap or cover, and if so, what type? Are containment structures maintained, and if so, at what intervals does this maintenance occur?
- Name and quantity of hazardous substances and contaminated media found in each source, including past and current disposals. If actual quantities are unknown, use estimates based on areal extent or volume (from dimensions of the release area). If available, provide documentation in the form of analytical results and manifests.
- Documented releases of hazardous substances - A release is defined as any spilling, leaking, pumping, pouring, emitting, emptying, discharging, injecting, escaping, leaching, dumping, or disposing into the environment. Releases include the abandonment or discarding of barrels, containers, and other closed receptacles containing a hazardous substance. Releases exclude the following:
- Releases that result in exposure to a person solely within a workplace with respect to a claim that the person may assert against the person's employer under ORS chapter 656 (i.e., OSHA).
- Emissions from the engine exhaust of a motor vehicle, rolling stock, aircraft, vessel (watercraft), or pipeline pumping station engine.
- Any release of source, by product or special nuclear material from a nuclear incident, as those terms are defined in the Atomic Energy Act of 1954, as amended, or any removal, remedial action, or release of source, by-product or special nuclear material from any processing site designated under section 102(a)(1) or 302(a) of the Uranium Mill Tailings Radiation Control Act of 1978.
- The normal application of fertilizer.
A release can be verified through visual or analytical evidence, facility documentation, or owner/operator admission.
- Pathways affected or potentially affected - Is the source contributing to contaminant migration? A pathway is the route by which a hazardous substance can migrate to a target or receptor. Four pathways are used to evaluate a site: 1) groundwater; 2) surface water; 3) air; and 4) direct contact (soil).
- Disposal history (both on- and off-site) for each waste type, including names of companies contracted with for disposal, and locations of disposal.
- Accessibility to source by the public and on-site workers, including whether the source is fenced, the extent of fencing, and type of security present.
- Regional geology and hydrology - This description includes the following (if applicable and available): physiographic setting; the general nature of geologic units; controlling regional geologic features; regional aquifers/aquitards; important drinking-water aquifers and/or confining units; regional groundwater depth and flow direction; and unusual and/or important hydrologic features.
- Site-specific geology and hydrology - This description includes (if applicable and available): geologic units beneath the site and their thicknesses, origin of deposits (channel sand, lake deposits, etc.), and any special features that would affect flow of contaminants through these units; local features that could impact groundwater and/or contaminant flow around site (faults or other controlling structures, confining layers, caliche zones, etc.); well log data; subsurface soil characteristics, including the least permeable continuous subsurface soil layer with a minimum thickness of 15 feet (used to determine subsurface hydraulic conductivity); aquifer/aquitard system beneath and in vicinity of site; important drinking water aquifers; and depth to groundwater at or near the site, if this information is available.
- Annual net precipitation - from the nearest weather station. This is a measure of total precipitation minus total evapotranspiration. Summed monthly differences between these two are used to calculate this score. (Where monthly net precipitation is less than zero, zero is entered for that month’s total.)
- Groundwater use - Groundwater use and population over a nine-section area (the USGS section in which the site is located and the eight surrounding sections). If a site is located on or near a section boundary, add any additional sections to the search, as appropriate. Include in the discussion: 1) aquifer(s) of concern - aquifers in use and the types of uses (private or municipal supply, back-up supply, alternate supply, etc.); 2) number of users, with an explanation of how this number is derived; 3) location of and distance to the nearest drinking water well, including well depth and current use; and 4) availability and accessibility of alternate drinking water supplies in the site vicinity.
- Surface water bodies within 2 miles downgradient of the site – including intermittent streams. Artificial ditches that do not connect to other surface water bodies are not considered surface water. If storm drains and sewers are part of the drainage pattern, include information on the inlet locations, and for storm drains, the outlet locations. The discussion should include distance to surface water - if more than one, include distance for each, name(s) of surface water body, and location in relation to site.
- Surface soil characteristics – to provide context for runon/runoff potential; this should include a discussion of soil type/constituents and permeability.
- Maximum 2-year, 24-hour rainfall.
- Floodplain - Is all or part of the site in a 100-year or 500-year floodplain?
- Terrain slope - Calculated from the point of contamination to the closest surface water body. Presented as percent slope and determined by the equation (rise/run) x 100, where rise is the change in elevation between the point of contamination and the nearest surface water body, and run is the horizontal distance between the two.
Surface water targets
- Surface water intakes within 2 miles downgradient of hazardous substances that could migrate off-site. List the use(s) of the water and population served, the name of the water district or user(s) accessing the intake, the location of the intake, the distance between the intake and point of contamination, and acres of land irrigated (if applicable).
- Recreational use of surface water body within 2 miles of the site. For each type of recreational use, describe type, location, and distance from site.
- Sensitive Environments or fishery resources within 2 miles downgradient. Sensitive Environments are defined in OAR 340-122-115 as: areas of particular environmental value where a hazardous substance could pose a greater threat than in other non-sensitive areas. These include: Critical habitat for federally endangered or threatened species; National Park, Monument, National Marine Sanctuary, National Recreational Area, National Wildlife Refuge, National Forest Campgrounds, recreational areas, game management areas, wildlife management areas; designated federal Wilderness Areas; wetlands (freshwater, estuarine, or coastal); wild and scenic rivers; state parks; state wildlife refuges; habitat designated for state endangered species; fishery resources; state designated natural areas; county or municipal parks; and other significant open spaces and natural resources protected under Goal 5 of Oregon's Statewide Planning Goals. The presence or nesting place of an endangered species is not a Sensitive Environment; the area in question must be designated critical habitat to be considered a Sensitive Environment. This is a federal designation - not all areas where endangered species are found are critical habitats.
A fisheries resource is as an area necessary for the maintenance of spawning or migratory pathways for anadromous or resident fish species. Anadromous fish return upstream from the ocean to their place of spawning. Resident fish live and breed in the same area.
Surface water conclusions
- Sources available to the air pathway and the quantity associated with each. Review each hazardous substance associated with these sources to determine whether air transport is gaseous or via particulates.
- Containment of sources of hazardous substances available to the air pathway.
- Predominant soil textural class of surface soils observed at the site.
Air pathway targets
- Distance from source of contamination to nearest population - Nearest population is considered the nearest dwelling, public building, park, or other area outside the facility boundary where people may be exposed to hazardous substances daily or seasonally. Include a description of the population type considered. If the nearest population is a dwelling, use a descriptive label such as "Smith residence."
- Population within a 0.5-mile radius of the source - measured from any on-site emission sources, this can consist of private residences, schools, businesses, rural residences, cities, towns, etc. A population can consist of one residence. Explain how this population was determined.
- Distance to nearest Sensitive Environment – See Surface Water Targets section for definition of Sensitive Environment.
Air pathway conclusions
- Sources available for direct contact and the quantity associated with each.
- Hazardous substances associated with sources available for direct contact.
- Accessibility - Could humans enter the site and contact hazardous substances directly rather than through air or water? Are there barriers that limit accessibility, such as fencing or security?
Direct contact targets
- Nearby residences - those residences with property lines within 1,000 feet of the contaminated area, whether on- or off-site. Specify distance from source of contamination and number of residents within 1,000 feet.
- Other structures or activities with property lines within 1,000 feet of a contaminated area. This would apply to on-site or adjacent property, and include parks, schools, day care facilities, playgrounds, and fairgrounds. Include the distance of each (as applicable) from the point of contamination.
- Is site located in a Sensitive Environment? See Surface Water Targets section for definition of Sensitive Environment.
Direct contact conclusions
Summary and Conclusions
Summarize information presented in the PA, using the following as a guide:
- Pathway(s) affected or of concern.
- Documented problems - drinking water contamination, groundwater or surface water contamination, documented release, etc.
- Potential problems - what contamination is potentially present that has not been documented?
- Unique problems such as an abnormally high death rate among cattle that drink from a creek downstream of the site, a high incidence of cancer among area residents, odor or strange color in well water, etc.
A brief statement of recommended further actions follows the summary of key information. Actions might include sampling of groundwater to determine if neighboring wells have been affected; a full remedial investigation; an XPA to obtain samples to confirm suspected contamination; fencing or other measures to control public access; or no further action.
All factual information presented in the report should be documented with reliable sources such as: letters from owners/operators and government agencies; reports on past waste management practices; records of communication with site owners and state and local government; and first-hand observations by qualified government personnel. Information from other sources, such as past employees or nearby residents, can be presented in the report but should not be accepted as fact unless the information has been confirmed.
Attach a complete list of references used to prepare the report. List only those references that document information in the report. Each reference on the list should include (as applicable), the author, or conversation or letter participants, title or subject, date, pages, publisher, and journal name. Include with the report a copy of those references that are site-specific, such as record of communication, letters, or journal articles that are needed to understand the report. Do not attach common references, but identify them and indicate that they are not being included with the report. For books and other publications that are less common, copy title pages and pages referenced.
Photographs are a good way to document releases and other relevant site conditions. Either make color copies of photos, or digitize them. Black & white photocopies of color photos are not useful.
Finally, include a Site Visit Summary in the references. This is a written summary of information gathered during the site visit and should include area measurements of sources (ponds, landfills, etc.), information obtained during the interview, and observations made during the site tour.