Department of Health Seal

TGM for the Implementation of the Hawai'i State Contingency Plan
Subsection 5.10


Investigation-derived waste (IDW) generated during the collection of environmental samples must be properly managed and disposed of following completion of the investigation. Typical types of IDW include (after USEPA 2014; see also USEPA 1991, SERAS 1994):

  • Personal protective equipment (PPE, e.g. disposable coveralls, gloves, booties, respirator canisters, splash suits, etc.)
  • Disposable sampling equipment and related items (e.g., plastic trowels, core samplers, broken or unused sample containers, sample container boxes, tape, etc.);
  • Soil cuttings from drilling or hand augering;
  • Drilling mud or water used for mud or water rotary drilling;
  • Decontamination wash water, rags, towels, etc.;
  • Spent solvents used in sample preparation (e.g., methanol preservation) or cleaning;
  • Other non-hazardous waste (plastic ground cloths, packing and shipping materials, etc.).

An effort should be made to minimize the amount of IDW generated during a site investigation to the extent practicable.

It is the responsibility of the property owner and the party conducting the sampling to properly dispose of all waste generated in accordance with local, state and federal regulations. If IDW is designated for disposal to a landfill or any other off-site location then the generator must make a Hazardous Waste Determination under RCRA (Resource Conservation and Recovery Act) and in accordance with Hawai‘i Administrative Rules (HAR) §11-262-11. Material that meets the regulatory classification as "hazardous waste" must be disposed of at a permitted, hazardous waste treatment, storage or disposal facility. There are currently no hazardous waste landfills in Hawai‘i. Therefore, IDW classifiable as hazardous waste must be disposed of at a regulated facility on the mainland.

A hazardous waste determination is a step-by-step process. First determine if the waste is specifically exempted by HAR §11-261-4. Petroleum-contaminated soil and materials are also excluded from hazardous waste regulations and can be disposed of at a municipal landfill, provided that it does not contain other contaminants which could cause it to be classifiable as hazardous waste. Wastes that are not specifically excluded are further assessed as part of the hazardous waste determination as follows (HAR 11-261-2):

  • Listed Wastes: Specifically listed as a hazardous waste in HAR §11-261-2 (F-listed waste)
  • Testing - Testing the waste for toxicity, ignitability, corrosivity, or reactivity according to the methods set forth in subchapter C of HAR §11-261; and/or
  • Knowledge (e.g., known flammable solvent; see also Construction and Demolition Waste Disposal General Guidance (HDOH, 2015 and updates).

Waste that meet criteria for classification of "hazardous" under these methods must be disposed of at a permitted facility. Categorization as a "listed" hazardous waste primarily applies to pure product (e.g., some pesticides) or process wastes (e.g. spent methanol and other solvent) and is not generally applicable to IDW. Hazardous waste regulations most commonly apply to excess soil that fails a leaching test criteria for disposal in a municipal landfill, referred to as the Toxicity Characteristics Leaching Procedure (TCLP). These materials must be managed as hazardous waste and disposed of accordingly at a permitted facility.

Soil, including borehole cuttings, that is not classifiable as hazardous waste can be placed on site or disposed of as follows:

Soil meets Tier 1 EALs for unrestricted land use (e.g., residential):

  • No restrictions on reuse provided that DU volume is <100 yd¬≥ (see HDOH, 2017d).

Soil fails Tier 1 EALs but meets commercial/industrial EALs and appropriate for current site use:

  • Place within the area where the soil was collected (surface soil).
  • Put back into the boring (subsurface cores);
  • Place in an on-site disposal unit (any disposal unit exceeding one cubic yard should be discussed with the HDOH SHWB to evaluate if a permit is required);
  • Transport to a HDOH-permitted off-site treatment/disposal facility.

Long-term management under an EHMP is required for soil that fails Tier 1 EALs for unrestricted reuse (or alternative, approved action levels) but is to be left on site (Section 13; see also HDOH, 2007). Soil that fails Tier 1 EALs but meets commercial/industrial EALs should not be placed in otherwise clean areas of the site or taken offsite for reuse at another location.

For decontamination fluids:

  • Pour onto ground in area where samples were collected to allow infiltration or evaporation;
  • Transport to a HDOH-permitted off-site treatment/disposal facility.

Used disposable tools, PPE, waste rags, towels, packing material, ground cloths, etc., (maximum 100kg per site investigation in order to qualify for small quantity generator exemption; refer to USEPA 1991, 2014).

  • Double bag and dispose of in an on-site trash container, at a waste collection center, or a municipal landfill.

Always check with the landfill operators to determine their acceptance and testing requirements (if applicable) for non-hazardous IDW materials being disposed. The generation of hazardous IDW should be minimized. Most routine investigations should not produce any hazardous IDW. The use of solvents for cleaning of equipment should be minimized (USEPA 2014). Solvent-free cleaning procedures for routine cleaning and decontamination as described in Section should be referred to (see also USEPA 2015). If the use of solvents is required, for example at sites impacted with tarry material, the volume should be minimized and mixing of waste solvent with detergent/wash water mixes avoided.

Management and disposal of waste groundwater generated during developing and purging activities is discussed in Section 6 and summarized below. Development and purge water can be disposed of on the ground immediately downgradient of the well provided that it is generated from the uppermost groundwater unit, is not impacted above action levels applicable to the site, does not contain free product or exhibit a sheen, and is not allowed to runoff into a surface water body or storm drain (refer to USEPA 2014). If these criteria cannot be met then the water must be disposed of at an offsite, regulated facility (e.g., municipal landfill or other treatment facility). Development and purge water should not be disposed in monitoring wells. Non-hazardous IDW such as drill cuttings, drilling mud, purge or development water, decontamination wash water, etc., should not be disposed of in dumpsters. [Note that guidance presented above replaces and supersedes guidance presented in the 2009 version of Section 6; scheduled for updates in 2017]

If knowledge of the contaminant or analytical testing determines the IDW falls under hazardous waste regulations then the material must either be (1) managed off-site at a permitted facility approved for the waste or (2) stored securely on-site in accordance with HAR §11-262-34, unless HAR §11-261-5 is applicable. Regulated hazardous waste left on-site must be handled in a fashion that does not pose an immediate threat to human health or the environment. The Solid and Hazardous Waste Branch (SHWB) should be contacted for concurrence with the manner of treatment or handling of IDW characterized as hazardous waste. The proximity of residents and workers in the surrounding area and site security must be considered before deciding to leave hazardous waste on site.