Please note: This summary is provided to help you understand the regulations. Consult the references provided for links to the full text of the regulations.
Crossties (Railroad) Recycling and Disposal
This section provides information about environmental rules that affect the recycling and disposal of used creosote-treated wood railway crossties.
Who is covered by the regulations?
Any facility that generates, collects, recycles, or disposes of used railway ties may be subject to environmental regulations that are mandated by federal, state and local agencies.
What is the purpose of the regulations?
Regulations have been developed to address two potential problems with used crosstie disposal:
Improper burning of crossties can emit toxic air pollutants generated from the wood preservatives in the ties
- Used crossties account for large volumes of waste, which can be a problem particularly in areas where landfill space is limited
Burning of used crossties in facilities other than cogeneration plants (combined heat and power plants, see below) is covered under Federal regulations. Landfill restrictions are generally covered under state and local regulations.
Wood railway ties account for over 93% of the more than 680 million crossties in use on US railroad track (others materials include concrete and plastic/composite). The ties, which are manufactured from oaks and other hardwoods, are pressure treated with creosote, which, under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), is an approved registered pesticide for this purpose (see: Creosote and its Use as a Wood Preservative). The average useful life of a railroad tie is about 40 years (longer in dry climates, shorter in wet climates). When ties are broken or worn out, the ties are removed from service and replaced. Approximately 16 million US railway ties are replaced each year. The used ties are stored, recycled and/or disposed of, with the majority being shredded at processing yards and subsequently burned as biofuel at cogeneration plants (see video covering tie replacement, shredding and use as fuel).
Regulations exist on the federal, state and local levels with regard to used wood railway crossties. The rules are primarily in place due to the presence of creosote, although the shear volume of crossties also has an influence. Creosote is a mixture of 200-250 identifiable substances; of these, 85% are polyaromatic hydrocarbons (PAHs) and the rest are cyclic heteronuclear nitrogen and oxygen containing substances. EPA has determined that creosote is a probable human carcinogen and several case reports of human carcinomas associated with exposure to creosote have been published. In terms of creosote leaching from crossties and entering the environment, studies indicate that most (85%) of the PAHs stay within the treated wood. However, when creosote products are burned the creosote evaporates and pollutes the air, unless controls are in place.
Some states have beneficial use rules in place that reduce the regulatory burden associated with reuse or burning of crossties, thereby encouraging alternatives to landfilling. For example, in some states, the use of crossties as landscaping timbers is a pre-approved beneficial use.
Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). Creosote, like all pesticide products, is comprehensively regulated by the U.S. Environmental Protection Agency (EPA) under FIFRA. All creosote manufacturers must obtain and maintain FIFRA registrations for their creosote wood preservative products. Under EPA’s “treated articles exemption,” railroad crossties, utility poles and other wood products that have been pressure-treated with FIFRA-registered creosote wood preservatives are not subject to FIFRA regulation (see 40 CFR 152.25(a)).
Under FIFRA, EPA has developed a preliminary risk assessment for creosote. Among other aspects of the assessment, EPA published safety precautions for handling creosote treated wood products for workers and also discusses use of crossties for residential landscaping.
Resource Conservation and Recovery Act (RCRA). RCRA is the primary US law governing the disposal of solid waste (subtitle D) and hazardous waste (subtitle C). Used ties are generally not classified a hazardous waste under federal law because they are not a "listed waste" and an abundance of testing has demonstrated that they do not exhibit a hazardous characteristic. However, waste generators cannot automatically assume used ties destined for disposal are non-hazardous. Under the Resource Conservation and Recovery Act, waste generators are required to perform their own hazardous waste determination. For more information on hazardous waste determinations for crossties, see the crosstie industry supported publication Management of Used Treated Wood Products.
Federal Air Pollution Regulations. An important federal rule that impacts burning of crossties is the Non-Hazardous Secondary Materials (NHSM) rule. This rule determines which specific non-hazardous secondary materials are, or are not, solid wastes when burned in combustion units (e.g., incinerators/boilers). Materials, such as crossties, that are not yet approved as a fuel are considered solid waste. As such, any boiler that burns crossties must be permitted as a Commercial, Industrial and Solid Waste Incinerator (CISWI). Because CISWI air pollution rules are more stringent than the regulations for common boilers, the owners of common boilers are unlikely to seek a CISWI permit, and therefore cannot burn crossties. There is an important exception to this rule. A combustion device that is otherwise subject to CISWI, but produces combined heat and power (CHP) is not currently subject to CISWI. These units, commonly referred to as cogeneration plants, presently account for the largest disposal method for crossties.
The NHSM rule that causes crossties to remain a solid waste is not unchangeable. Revisions to the rule were signed by EPA as recently as 2012 that included other wood residuals, such as resinated wood, in the list of materials considered to be fuels, not wastes. Importantly, in the 2012 revisions, EPA made specific reference to an industry petition on creosote-treated crossties, and stated that if additional information is submitted by industry to support their position, that EPA would reconsider classifying creosote-treated crossties as fuels. For the latest information on this subject, check EPA's Non-Hazardous Secondary Materials rule page.
State and Local Regulations. State and local regulations may preclude the disposal of used crossties in municipal landfills and/or require that disposal be limited to special landfills, such as permitted construction/demolition (C&D) disposal landfills. These regulations may cover pressure treated wood in general and/or explicitly regulate crossties (e.g., see Management of Used Treated Wood Products - Addendum For the Western United States). In particular, California has addressed treated wood waste and approves landfills for disposal of this material. New York also has specific rules governing creosote and creosote treated wood products. In New York, creosote or products containing creosote cannot be manufactured, sold or used. However, a number of exemptions exist, including railroads.
State regulations may also affect the storage of used crossties that are destined for disposal. For example, in Washington, creosote treated wood must be removed from the generator’s site within 180 days.
Because state rules affecting crosstie disposal vary so widely, generators are urged to fully investigate the rules that apply in their state. More information on state regulations for disposal of solid wastes and C&D wastes can be found in the Solid Waste State Resource Locator. This resource includes links to state regulations, permitted landfill lists and environmental agency contacts.
Many states have beneficial use provisions within their solid waste regulations. These rules allow for "beneficial use determinations" (BUDs). When operating under a BUD, the specific wastes used by a generator or end user in the approved manner are not considered solid wastes (note that specific provisions of beneficial use regulations vary by state).
The following states have approved crossties for beneficial use either on a case-by-case or pre-approved basis:
See the Beneficial Use Portal for more information.
Recycling/disposal options vary by location due to the availability of secondary materials markets and state and local rules. In 2008, the Railroad Tie Association (RTA) conducted a crosstie disposal survey. The results are:
Disposed of by approved/permitted cogeneration: 53.77%
Reused for commercial landscaping: 14.40%
Reused for residential landscaping: 14.36%
Reused for commercial farms (fence posts, etc.): 5.17%
Disposed of in approved/permitted landfills: 5.12%
Reused as cascaded ties for railroad application: 4.70%
Disposed of by approved/permitted gasification: 2.49%
The most widely used disposal option is use as a biofuel in cogeneration plants. Prior to burning as a fuel, the crossties are shredded using heavy-duty equipment that can process 20 tons of crossties per hour. The shredded material is then hauled to a cogeneration plant for use as fuel.
Railroad Tie Association (RTA). Organized in 1919 and with predecessor groups dating back to the late 1800s, RTA's mission is to provide the forum and direction for the continual improvement in the life-cycle of the engineered wood crosstie system. The RTA website includes a very informative section with frequently asked questions (FAQs), a waste management and recycling directory and a list of environmental literature.
Life Cycle Analysis of Creosote Treated Ties in the US Comparison Paper (2013). This crosstie industry supported paper compares the cradle-to-grave environmental life cycle assessment (LCA) results of creosote-treated wooden railroad crossties with the primary alternative products: concrete and plastic composite (P/C) crossties.