Is Your Mulch Processing Facility in Compliance with the Law?

New Regulations took Effect on November 4, 2017

Effective November 4, 2017, Mulch Processing Facilities in the state of New York are subject to regulation under the state’s revised and updated Solid Waste Management Facilities rules. Mulch Processing Facilities create a product derived from tree debris, yard trimmings, and other suitable woody material, which is intended for use on soil surfaces to prevent the growth of weeds and minimize erosion. The New York Department of Environmental Conservation (NYSDEC) is regulating the production and storage of mulch in order to reduce environmental impacts including dust, odor, adverse water quality, and fires.

A Mulch Processing Facility is defined as a facility that processes yard trimmings (other than grass clippings), tree debris, and wood debris into mulch. On December 28, 2017, the New York Department of Environmental Conservation announced the availability of a new guidance document intended to assist the owners and operators of mulch processing facilities.

The following are not regulated as a Mulch Processing Facility, but are subject to separate and distinct regulation under the NYSDEC’s full set of Solid Waste Management Facilities codes and regulations:

  •  the processing of construction and demolition (C&D) debris into mulch;
  •  a facility for combustion or thermal treatment; and
  •  a facility that composts yard trimmings.

For purposes of clarification, unlike the processing of mulch, composting is the aerobic, thermophilic decomposition of organic waste to produce a stable, humus‐like soil amendment used as a source of nutrients, organic matter, liming value, etc.

 Regulatory Overview

Mulch Processing Facilities are regulated under one of three different ‘tiers’ based on the total quantity of material on site at any given time, including both incoming material as well as processed material. The three regulatory tiers consist of exempt facilities and those that need to either be registered or permitted. See the chart below for a breakdown of the three regulatory categories.

In addition to the types and quantities of materials accepted, facilities will be held to one or more of the following:

  •  pile size and separation distance restrictions;
  •  contaminant preclusion and removal;
  •  the marketing and movement of their product;
  •  storage restrictions and time frames;
  • temperature monitoring and pile restacking (See Page 8);
  •  the development of run‐on and run‐off plans; and
  •  buffer zones from properties and water resources.

Adulterated or Contaminated Materials

Mulch Processing Facilities can accept, process, and store the following materials:

  •  yard trimmings (other than grass clippings);
  • tree debris including tree and shrub parts, including branches, stumps, and trunks, as well as other similar woody vegetation;
  • wood debris including unadulterated wood pallets and unadulterated wood that originates from wood product manufacturing or other similar sources; and
  • finished mulch products generated elsewhere.

Mulch Processing Facilities are not permitted to accept, process, or store the following materials:

  •  construction and demolition (C&D) debris; and
  • adulterated or contaminated wood.

Spotting contamination in a waste source or finished product pile can be challenging. Contamination can range from unwanted additions to the pile such as rocks and plastic, to adulterated or contaminated wood products. Physical contaminants can damage the processing equipment, and lead to a low-quality product. Adulterated or contaminated wood can pose a significant health risk when exposed to humans, wildlife, and the environment.

Types of adulterated or contaminated wood:

  • adhesives and paint;
  • creosote‐treated wood;
  • CCA‐treated wood;
  • asbestos‐contaminated material; and
  • other pesticide or pressure treated lumber.


CCA Treated Lumber

CCA‐treated lumber

often has a visibly greenish hue





Creosote‐treated lumber is found frequently in railroad ties and marine structures




Small Contaminates


Small contaminants

from mulch



Mulch tiers










Types of physical contamination

  •  plastics
  • C&D debris
  • rocks, stones
  • garbage, strings and rope; and
  • materials that will readily compost and generate heat.

Odor Issues

When managed properly, and only exposed to aerobic conditions, mulch piles should not produce objectionable odors. Facilities must be mindful of neighbors – odor inspections should be conducted along the perimeter of the facility, recorded, and any odor complaints need to be addressed. If necessary, the use of odor neutralizing sprays can be implemented. However, it is important to note that objectionable odors from a mulch pile may be indicative of other issues. If piles become too large, hot, or wet, they may undergo anaerobic decomposition, and thus emit odors. For double ground mulch, keeping these piles as a coarse grind while they “age” until they are closer to sale can minimize odor risks. Turning or restacking piles can also help to prevent odors (see: Fire Risk and Safety section) and should be done under wind conditions that minimize offsite impacts.

Pile Size and Storage Limitations

Pile size limitations in Part 361‐4 are based on the type of grind the material has been through as well as the location of the facility.

Piles must be triangular in cross‐section and sized to minimize anaerobic conditions within the pile, which will limit odor impacts as well as reduce the risk of fires. Note: All piles must be at least 10 feet apart. Standing water on the storage area must be minimized.

Recordkeeping and Reporting

All facilities must keep records of daily operations and must report annually to DEC by March 1st of each year.

Site Design Criteria

Mulch Processing Facilities must employ best management practices appropriate to their operation to restrict the amount of run‐on and

run‐off generated on the site. Facilities must also adhere to specified buffer zones between property, water features, and all materials (including both processing and storage, listed below).

Pollution Prevention

Mulch processing sites must take care to prevent water pollution resulting from their processing activities. Because water both entering and exiting the site have the potential to bring in and off contaminants, all registered and permitted facilities must have a written run‐on and run‐off plan that is approved by DEC.

The water sources listed above can contain many different contaminants:

  • Nutrients
  • Turbidity

Fire Risk and Safety

Tree debris and wood debris are highly combustible and there are many ways a mulch pile could catch fire, either spontaneously or through human action. These fires are difficult to extinguish and have a high risk of spreading to nearby piles and structures. It is important for facilities to have a plan in place and work with their local fire departments to ensure preparedness in case of a fire emergency (including planning for a reliable water supply).

Myth: Driving heavy machinery on mulch piles to process them for a better product, compress them for added space, and reach the tops of piles are part of normal operation.

Compressing a mulch pile (making it denser) is known to cause spontaneous fires. When the pile is compressed, aeration is stopped, and the pile becomes anaerobic and begins to ‘cook.’ Temperatures can easily reach unsafe levels.

When oxygen/air is introduced suddenly into a hot, anaerobic pile, flash fires can occur. Keep the piles loose!


Kevin C. Murphy is a member of the Wladis Law Firm, P.C., located in Syracuse, New York. If you or your municipality operates a mulch processing facility or any other waste management facilities and have questions or need assistance in complying with new, amended or longstanding solid waste management regulations or any type of environmental compliance, permitting or enforcement issues, including the threat of a potential environmental criminal prosecution, please feel free to contact Attorney Murphy or Attorney Timothy Lambrecht of the Wladis Law Firm. Mr. Murphy previously served as a senior trial attorney with the U. S. Department of Justice Environmental Crimes Section and regularly represents clients in defending against alleged criminal violations of federal, state and local environmental laws.







Kevin Murphy Headshot

Kevin C. Murphy

Kevin C. Murphy concentrates his practice in the areas of environmental compliance and litigation; environmental and white-collar criminal defense, and complex litigation matters. Mr. Murphy is a graduate of the University of Virginia School of Law and a former senior trial attorney with both the Kings County (NY) District Attorney’s office and the U.S. Department of Justice Environmental Crimes Section in Washington, D.C. He previously taught a seminar on environmental criminal enforcement at the Syracuse University School of Law and has been listed in The Best Lawyers in America.

More Details About Kevin C. Murphy