proposed designation of yard trimmings compost because there are a lack of national
standards for this item.
The Agency does not believe that a lack of national standards will inhibit the general
use of yard trimmings compost, or that national standards are a necessary prerequisite for its
designation. As noted in the preamble to the proposed rule, compost can have many
different applications, each of which may require compost with differing characteristics. F o r
instance, using compost for turf establishment would typically require a mature, cured
compost, while an application for landfill cover might utilize less mature compost. As
explained in EPA's draft RMAN issued concurrently with the proposed CPG, the State of.
Maine has developed quality standards for six different types of compost ranging from.
topsoil (three classes), to wetlands substrate, to mulch (two classes) (see 59 FR 18906, April
20,1994). These standards are being used by many state agencies in purchasing compost
and can serve as a guide to anyone purchasing this item. In addition to the guidance
afforded by the State of Maine's quality standards, compost suppliers can assist procuring
agencies in determining the type(s) of compost needed for particular applications. The
agency recommends, therefore; that when purchasing yard trimmings compost, the specific
use of the compost should be described to the supplier to ensure the purchase of a product
compatible with the intended use.
In the preamble to the proposed CPG, EPA also noted that the Composting Council, a
diverse group of professionals engaged in promoting the beneficial use of compost, as well as
a number of state agencies, are developing standards and specifications for compost (see 59
FR 18878, April 20, 1994). As these standards are developed, EPA will make their.
availability known to procuring agencies by referencing them in a future Recovered Materials
3. Rationale for Designation
EPA believes that yard trimmings compost satisfies the statutory criteria for selecting
items for designation.
a. Use of materials in solid waste. As discussed above in section II.A, yard debris
(leaves, lawn clippings, bush and tree trimmings) comprise 16 percent of the municipal waste
stream. These materials can be composted and used as soil amendments, rather than
landfilled or incinerated. Thus, the use of compost can significantly reduce the amount of
yard trimmings, grass clippings, and leaves disposed in landfills and reduce one source of
methane emissions from landfills.
b. Technically proven uses. Adding compost to soils can improve their suitability for
plant growth. The organic matter in compost is particularly beneficial in poor soils. Adding
compost to clay soils reduces soil density and compaction, increases aeration, and increases
soil porosity and drainage. These changes lessen the danger of root rot disease. Compost
added to sandy soils binds soil particles to increase water and nutrient retention, as well as