Handling Pressure Treated Timbers

When the call comes in to clean up a construction or demolition project that involves pressure-treated timbers, the rules can be quite different than those for the average project. Some states have specific rules for handling treated timbers, although most treated wood is not considered a hazardous waste. However, many kinds of treated timbers are not appropriate for grinding into wood mulch.

In addition to the typical sources of treated wood like railroad ties and utility poles, treated C&D materials are found in warehouse floors, boat docks, outdoor decking around hotels and homes, and other buildings where weather-resistance is important.

Creosote, pentachlorophenol and water-borne timber treatments are the most common for recyc-lers to encounter. Water-borne treatments include chromated copper arsenate, ammoniacal copper quat, and ammoniacal copper zinc arsenate. In most cases, the chemical preservative, regardless of type, has been forced deep into the cellular structure of the wood in a closed cylinder under pressure.

Pressure treated materials are a whole different ball game than the typical C&D timbers from a normal knock-down job. For one, the quality of the wood may be better. A number of manufacturers guarantee treated wood to resist decay and termite attack for 40 years or more. But the options for disposing of it are limited.

In general, treated materials are safe to handle and safe to reuse and recycle. However, several common-sense handling precautions do apply. According to Allan Wilbur, director of public affairs for the American Wood Preservers Institute, Vienna, Va., the U.S. Environmental Protection Agency regulates treated materials under the Resource Conservation and Recovery Act. Toxicity, ignitability, corrosiveness, and reactiveness are the major concerns. "The number one consideration usually is toxicity," Wilbur says.

EPA’s Toxicity Characteristics Leaching Procedure establishes the thresholds for 39 different chemicals. If, after applying the TCLP test to a particular set of timbers, the extract contains concentrations of chemical constituents above any of the 39 chemical-specific regulatory levels, the waste is classified as hazardous. The materials in a wood sample depend on the type of preservative used. Some preservatives do not contain any TCLP constituents.

"TCLP testing of penta and creosote treated wood has conclusively demonstrated that treated wood products are not a ‘hazardous waste,’" according to Wilbur.

Jim Graham, professional engineer with the National Timber Pilings Coun-cil (NTPC) in Rye, N.Y., echoes most others in the industry when he says that the first choice for handling old wood is to reuse it in some manner. Some of the pilings in docks and piers, especially on the East Coast, are 100 years old. But the timbers are quite recyclable. "It’s all natural material," he says. "The wood is from the forests and the creosote is a byproduct of coke."

While re-use in an identical setting is the first level of reuse, it takes an expert’s eye to determine whether there is in-ternal rot in a timber or piling. "If you pick at it, you’ll see pretty soon if there is rot," he says. But, he notes, there can be a lot of life in rather old timbers.

If the timbers can’t be reused in the exact same way, there are alternatives, such as landscaping timbers and parking lot bumpers. This is considered the next lower level of use.

The lowest, but perhaps most com-mon use, is burning the timbers for energy production. Research by Frost & Sullivan, a consulting group in Mountain View, Calif., says the waste-to-energy market will grow from $2.14 billion last year to nearly $3 billion by 2001, a five percent compound annual growth rate.

CCA-treated wood and material treated with fire retardants present a host of challenges for recyclers. Since many railroads and utility companies have arrangements for internal recycling of rail ties or telephone poles, those items rarely come into the general market in bulk. However, it is not unusual to find treated materials which were used in volume for landscaping or for shipping docks and other outdoor uses.

David Webb, manager of quality assurance and technical services for Koppers, Pittsburgh, Pa., says that roughly 20 percent to 25 percent of the treated railroad ties taken out of a rail line can be rehabilitated. Material processed through a facility like Koppers’ Portsmouth, Ohio, operation generally is put back into use on sidings and yards, not mainlines. "Railroads get good service from their recycled ties," he says.

Another 25 percent of cross ties is good enough for landscaping use. Most of the remaining 40 percent to 50 percent is burned as co-generated fuel. Koppers has permitted facilities in Florence, S.C.; Montgomery, Ala.; Grenada, Miss.; and Muncy, Pa. The company is just opening a facility in Orrville, Calif., which has a permit to burn creosote-treated wood chips.

The remainder of the treated materials goes to the dump as industrial waste. CCA and pentachlorophenol treated materials represent less than 2 percent of the utility and railroad market today, although that may expand with time. Most CCA material is used by homeowners and disposed of through normal trash collection.

Any C&D operation can stumble into projects requiring contact with treated materials. While there are no firms which specialize solely in recovering treated materials, the jobs do show up regularly, says Michael Taylor, executive director of the National Association of Demolition Contractors, Doylestown, Pa. However, NADC does not delineate the wood fraction of a recycling job into types of wood or treated versus untreated materials.

Most of the wood products treated with water-borne materials are used in the construction of residential decking and walkways, fences, gazebos, boat docks and playground equipment. However, an increasing amount is seen in highway noise barriers, sign posts and retaining walls.

"CCA is relatively new in the market so you don’t see much of it," NTPC’s Graham says. "It hasn’t been around long enough that you’d expect to find it in buildings or piers being torn down. Penta will show up mainly in utility poles, not in construction."

One of the largest C&D projects dealing with treated materials was the dismantling of the Navy Pier on Lake Michigan. Brandenburg Industrial Services, Chicago, handled the project.

Brandenburg treated most of the materials as Class D waste, which is typical for that kind of job. But before the company made any moves, company officials took a close look at the materials. "The first thing we do when we look at a job with a large volume of treated materials is pull a sample and test for toxics," says Dave Smaniotto, Brandenburg’s environmental specialist. The company tries to take samples from the most heavily colored timbers, looking for the four or five constituents which are most likely to appear in the sample as hazardous material.

Almost all of the materials Branden-burg has dealt with over the years have come back as non-hazardous under the EPA guidelines, and the jobs are bid as such.

Little of the material that Branden-burg pulls out of its Midwestern sites is recycled. "Recycling operations can’t handle the volume of material," Smaniotto explains. Since tipping fees in the Midwest are relatively low, and most Illinois landfills can handle Class D material, putting the materials in a landfill is the most practical way to go.

In some cases, such as pine decking, there is an aftermarket and those materials will be handled accordingly. "One thing you want to be sure of is that you don’t mix treated with untreated materials. If you cross-contaminate treated with good timbers, you take a cut in aftermarket value," Smaniotto says.

Buyers like John Williams, vice president for Mountain Lumber Co., Ruckersville, Va., who are looking for building material-quality timbers generally avoid pressure treated materials. "It indicates that it is young wood. I look for old timbers. You can’t make flooring out of pressure treated wood," he says.

Large, creosoted timbers may have value to Williams if the beams are thick enough to cut the creosoted surfaces off and still have a good-sized beam. "An old pier, circa 1890, where the creosote didn’t penetrate as well would be of interest," Williams says. If the material penetrated lightly through, then that part of the wood is sawed off and disposed of properly.

One of the most common sources of creosote-treated timbers is railroad ties. Jim Gauntt of the Railway Tie Association, Fayetteville, Ga., notes that some of the mainline railroads are working with firms for internal recycling of ties. "When ties get taken out of mainline track, sometimes they are cascaded down to lower-use track," he says.

Other typical uses of creosote-treated timbers are in guardrail posts, highway bridges and marine structures like bulkheads and seawalls. Recycled ties and other creosote-treated timbers can be used in co-generation operations or as fuel-enhancers in other burning operations.

"None of these treated materials are hazardous waste," Webb says. "They do not trigger the toxicity laws."

The bulk of state regulations follow the same line of reasoning.

Most railroads utilities have their own programs in place for handling reuse of ties and poles. The market for wooden ties is not dwindling, despite the inroads made by steel, concrete and fiberglass poles. Still, 80 percent of the pole market is wood.

Despite the good environmental safety record of treated timbers, experts recommend a few precautions. For one, it is not a good idea to burn such wood in open fires or residential boilers because toxic chemicals can be produced in the smoke and ash.

With penta-treated wood, urethane, shellac, latex epoxy enamel and varnish are acceptable sealers. Coal tar pitch and coal tar pitch emulsion are effective sealers for creosote-treated wood-block flooring. Urethane, epoxy and shellac are acceptable sealers for creosote-treated wood.

Recycled penta-treated wood or creosote-treated wood should not be used in industrial, residential or commercial interiors, except for laminated beams or building components which are in ground contact and are subject to decay or insect infestation.

Likewise, avoid penta-treated materials in farm buildings where there may be direct contact with livestock which may bite or lick the wood. Such materials also should not be used in facilities where the preservative may become a component of food or animal feed.

Workers should avoid frequent, prolonged inhalation of sawdust from treated wood, wear protective clothing and dust masks, and wash before eating or drinking.