Ash Disposal

Ash removed from inside buildings and homes should be disposed in accordance with community plans and directions (for example, preparing it for pick up by clean-up crews as part of neighborhood cleanup activities). It may be advisable to request that people separate volcanic ash from normal garbage for collection or disposal at a designated location—mixing ash with normal garbage can result in damage to collection vehicles and can take up space in landfills. Small amounts of ash from vacuum cleaners have been disposed of successively in household gardens and lawns.

Disposal Sites

Ash removed from roads, buildings, and other structures should be disposed of in a place and manner that:
  1. does not create a new hazard to the public or adjacent landowners.
  2. does not allow wind or water to redistribute the ash.
  3. the ash does not have to be moved again.

Several disposal locations may be necessary in order to provide sufficient capacity for all the ash. Choosing quickly one or more disposal sites after an ashfall is often difficult. Ideally, potential disposal sites are identified before a volcanic eruption on a regional basis as part of a contingency-planning process. An appropriate siting process can be developed to identify potential sites for use by all organizations and public agencies involved in clean-up operations. This might include a request for landowners to volunteer parts of their property for ash disposal, if necessary. Responsibility for operating one or more disposal sites needs to be assigned to an appropriate organization or public agency.

Ash is generally regarded as good fill material, as it mixes well with soil, has good bearing strength for structural support, and supports vegetation growth if fertilized.
Desirable features of disposal sites (modified from Johnston and Becker, 2001):
  • Site is close to ash cleanup area(s).
  • Access exists for heavy vehicles from a main road.
  • Situated away from waterways (which could be affected by any leaching or chemicals from the ash or fine material washed from the ash).
  • Availability of soil for cover (although other forms of ground cover, including planting of rye grass, ivy, or use of pre-grown lawn/turf for immediate coverage, may be options).
  • End use of disposal site is compatible with ash deposits.
  • Meets local, regional, or national land-use requirements or laws.
Possible disposal sites (recommendations from U.S. Federal Emergency Management Agency, 1984):
  • Depressions on government-owned property.
  • Unused rights-of-way (which can benefit or remain undamaged from the increased grade level of the fill).
  • Abandoned rock quarries.
  • Old borrow pit or gravel/construction excavation site.
  • Low or hollow areas on private property where the owner is willing to accept full responsibility for stabilizing the ash (it is reasonable to expect private property owners to accept the material free of charge).
  • Farmland adjoining the rights-of-way (if acceptable to the farmers) where it can be incorporated into the cultivated land with no harmful effects; farmland in Eastern Washington on which ash from the 1980 eruption of Mount St. Helens was spread from adjacent roadways produced as much grain as sections of farmland without the ash.
  • Household gardens and lawns, if ashfall is light.
Strategies to prevent wind from stirring up ash from a disposal site (from U.S. Federal Emergency Management Agency, 1984):
  • Cover volcanic ash at disposal sites with a layer of heavy material such as soil or gravel.
  • Fertilize and seed the disposal site to start vegetation growing.
  • Use straw and other mulching materials to cover the ash.
  • See potential use of chemical dust suppressants based on experience from the 1980 eruption of Mount St. Helens.