Process for Evaluating and Remediating Burn Dump Sites

To All Local Enforcement Agencies:

This Local Enforcement Agency (LEA) Advisory covers the process for evaluating and remediating burn dump sites. The purpose of this LEA Advisory is to:

  • Provide guidance on the appropriate procedures to follow in evaluating the risks to public health and safety and the environment posed by burn ash dump (burn dump) sites that contain non-Resource Conservation and Recovery Act (RCRA) waste.
  • Identify the steps to take to control these risks.
  • Describe the roles of other regulatory agencies in burn dump regulation.
  • Address burn dump issues raised at the November 1997 Partnership 2000 Conference at Asilomar.

What Is a Burn Dump?

A burn dump is a site where solid waste has been burned at low temperature and the residual burn ash and debris have been landfilled or stockpiled. The burn ash referred to in this document is the residual ash that results from the low temperature combustion of solid waste. Ash from controlled incineration at a permitted facility, such as a waste-to-energy plant, is not included in this advisory.

Burn dumps typically contain little biodegradable organic material because of the combustion of waste materials and the age of the sites. Therefore, typically little or no landfill gas is being generated at burn dump sites.

Burn dumps were phased out in the early 1970s in response to federal and state air quality legislation. Most burn dumps are considered closed sites as their operations ceased prior to the development of regulations addressing the closure of disposal sites, provided that these sites were operated under applicable permits at the time. If these sites were not operated under applicable permits at the time they would be considered illegal disposal sites.

What Are the Problems and Hazards Associated with Burn Dumps?

An increasing number of burn dumps are identified in site assessments conducted by the LEAs and the California Integrated Waste Management Board (IWMB). Laboratory tests of ash from a number of burn dump sites show that the burning of nonhazardous household or municipal waste tends to concentrate certain metals to levels that are hazardous under California regulations and, on occasion, federal regulation. The potential threat from burn ash to public health and safety and the environment may be minimal if the sites are located in remote, less populated areas of the state where public contact is limited or nonexistent. However, in heavily developed areas where land is scarce and expensive there is increasing interest in developing burn dump sites. Before a burn dump site is developed the associated health and environmental risks should be addressed through a waste characterization study as described in Attachment 1.

Test results indicate the predominant metals of concern in burn ash (i.e., arsenic, beryllium, cadmium, chromium, copper, mercury, nickel, lead, and zinc) are not readily soluble in water; therefore, not readily leachable into ground water. However, burn ash does pose a risk if it becomes airborne, is eroded into surface water, or comes in contact with skin. The potential routes for human exposure to the contaminants in burn ash are inhalation, ingestion, and direct skin contact. Exposure to contaminants via any of these routes may result in adverse health effects. Attachment 2 briefly describes the adverse health effects of the metals most commonly found in burn ash. Burn dump problems and potential hazards result primarily from:

  1. Improper cover contributing to hazardous burn ash becoming airborne and being inhaled by humans or animals.
  2. Inadequate erosion protection contributing to transport of hazardous burn ash into surface waters and being ingested by humans and animals.
  3. Improper site security allowing human or animal access to areas of hazardous waste and hazards from direct contact, inhalation, and ingestion.
  4. Burn dumps not recorded at the local level allowing construction or other improper land use on or adjacent to hazardous burn ash and long term threats to public health and safety and the environment.

Burn Ash Characterization

The main concern when evaluating a burn dump is determining whether or not the burn ash and residues are hazardous. To determine whether or not a burn ash is hazardous a burn ash characterization study (i.e., waste characterization study) is performed. In a waste characterization study burn ash samples are taken and analyzed using a specified sampling methodology and set of test protocols. Each test protocol produces its own specific type of information for a given range of conditions. The waste characterization study is described in Attachment 1.

Who Regulates Burn Dumps?

LEA/IWMB Authority

The authority that allows LEAs and the IWMB to investigate and inspect burn dumps is contained in Public Resources Code (PRC) section 44100. This section states in part that:

….the enforcement agency, in issuing or reviewing any solid waste facilities permit or in connection with any action relating thereto or authorized by this division, may investigate the operation by any person of a …disposal site….

“Disposal site” is defined in PRC section 40122 which states in part:

“Disposal site” or “site” includes the place, location, tract of land, area, or premises in use, intended to be used, or which has been used, for the landfill disposal of solid wastes.

Solid waste is defined in PRC section 40191, which states that solid waste does not include hazardous waste or low level radioactive waste regulated under Chapter 7.6 of the Health and Safety Code. When burn ash is classified as a RCRA hazardous waste the IWMB and LEA do not have the authority to, and will not, regulate the site, even if the waste was derived from solid waste. However, when burn ash is classified as a California hazardous waste there are circumstances where the IWMB and LEA may regulate the burn dump site.

The burn ash at most burn dump sites in California meets the criteria to be classified as a California hazardous waste. However, because of the limited solubility of burn ash metals in water, the risk posed by these sites is effectively controlled when a few straightforward precautions are taken. To acknowledge this reduced risk under specified conditions IWMB and Department of Toxic Substances Control (DTSC) jointly developed a streamlined, coordinated regulatory approach for burn dump sites outlined in a memorandum dated March 3, 1995 (Attachment 5). Under this streamlined, coordinated regulatory approach the LEA and IWMB are given the responsibility to regulate burn dump sites, with limited DTSC involvement. Out of four scenarios in this streamlined approach DTSC involvement in required in only the fourth scenario. The approach is described in Attachment 3 and graphically represented in Figures ABC, and D.

Also, under some conditions the owner of a burn dump site may request from DTSC a nonhazardous determination or a blanket variance for closure. Under this scenario the IWMB and LEA may replace DTSC as the regulating agency. This is explained in more detail in following sections and attachments.

In the event that the waste characterization study demonstrates that the ash does not meet the criteria for being classified as a California or RCRA hazardous waste, DTSC involvement in any site activity, including removal of ash, would not be necessary. If the waste characterization study demonstrates that the ash contains a non-ash California hazardous waste fraction DTSC should be contacted to determine how to proceed. However, regardless of whether the ash is hazardous or not, the LEA should coordinate with the Regional Water Quality Control Board (RWQCB).

Also, California Code of Regulations, Title 27 (27 CCR) section 21100(d) allows the enforcement agency to apply closure regulations, on an as needed basis, to closed sites not having approved closure plans and to illegal or abandoned disposal sites. Section 21100(d) states that:

Closed sites for which closure plans were not approved pursuant to §20164 or §21099, and illegal or abandoned disposal sites which pose a threat to public health and safety or the environment shall implement the provisions of these regulations as required by the EA.

DTSC Authority

If burn ash is classified as a RCRA hazardous waste DTSC is the lead agency and regulates the site in accordance with California Code of Regulations, Title 22 (22 CCR). If burn ash is classified as a California hazardous waste DTSC would normally be the lead agency and would regulate the site in accordance with 22 CCR. However, as discussed above, under some circumstances the authority to regulate burn dump sites is given to the LEA and IWMB.

Regional Water Quality Control Board Authority

The RWQCB has authority to regulate burn dumps regardless of whether the waste has been determined to be hazardous or non-hazardous. Regulations that the RWQCB use to govern burn dump sites are contained in 27 CCR.

Proposed Changes to Hazardous Waste Regulations

Currently, DTSC is proposing changes to 22 CCR through a process termed the “Regulatory Structure Update” (RSU). Where most hazardous wastes are now subject to the same management standards DTSC is proposing to create two hazardous waste tiers based on risk, fully regulated hazardous waste and special waste. The first tier is for the higher risk waste streams, which are fully regulated hazardous wastes. This tier is subject to all hazardous waste regulatory requirements. These Tier 1 wastes would be regulated in the same way all hazardous waste is currently regulated in California. The second lower-risk tier would be special wastes. Tier 2 will be a more comprehensively defined waste category that includes a broader range of wastes. These Tier 2 wastes are lower-risk wastes than those in Tier 1 and have fewer regulatory requirements. Although special wastes would have fewer requirements there would be no reduction in protection of public health and safety and the environment. One possible result of DTSC’s RSU on the regulation of burn dump sites may be that some of these sites will fall into a lower category of risk; therefore, regulated at a lower level. Once DTSC completes the RSU process this advisory will be reviewed to determine if a revised/updated advisory is necessary.

What Procedures Should Be Followed to Regulate Burn Dumps?

Since most burn dumps can be classified as closed, illegal, or abandoned sites their identification and initial assessment should be accomplished using the Site Identification Process (SIP) or similar procedure. The guidance for the SIP is contained in LEA Advisory Numbers 3 and 9. The assessment in the SIP would determine whether there is an imminent threat to the environment or public health and safety. It is important that at a minimum the investigator evaluates the following:

  1. Degree of burn ash exposure.
  2. Adequacy of erosion control.
  3. Site security including fencing and signage.
  4. Whether the condition of the property is recorded showing the location of the burn dump, possible hazardous constituents present, excluded postclosure land uses (PCLU), and procedures for the development of the property for excluded land uses.

Additional areas of concern might include burning waste and underground fires.

Once this initial assessment has been completed, refer to Attachment 3 to determine the appropriate procedure to follow for the specific site. These procedures are intended to provide guidance for properly remediating burn dump sites.

Because site conditions will vary, some or part of the procedures or the level of detail may not be applicable in all cases. For example, in rural areas where there may be fewer sensitive receptors and a lower risk to human health and safety a less rigorous waste characterization may be appropriate. In urban areas, because of the higher concentration of sensitive receptors and higher human health and safety risks, a more rigorous waste characterization may be necessary. However, it is important that coordination occurs between all regulatory agencies to assure that the appropriate mitigation measures are implemented.

If you should have any questions regarding the regulation of burn dumps please contact the Remediation, Closure and Technical Services Branch staff person assigned to assist your jurisdiction.


Original signed by:

Julie Nauman, Acting Deputy Director
Permitting and Enforcement Division


Publication #231-98-019

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