{"hq_id":"hq-p-out-000007","name":"Pressure-treated lumber and CCA wood (playground equipment, decks, and landscape timbers)","category":{"primary":"outdoor","secondary":"outdoor / pressure-treated wood / CCA lumber / playground equipment / decks / arsenic exposure / legacy wood preservative","tags":["CCA wood arsenic","pressure-treated lumber arsenic","chromated copper arsenate playground","CCA playground equipment children","arsenic wood leaching","EPA 2003 CCA phase-out","legacy CCA deck arsenic","CCA wood soil contamination","children arsenic playground exposure","CCA wood sealer mitigation","ACQ replacement wood preservative","arsenic hand-to-mouth playground","urinary arsenic CCA playground children","CCA wood residential ban 2003","chromium VI CCA wood"]},"product_tier":"OUT","overall_risk_level":"high","description":"Chromated copper arsenate (CCA) is a wood preservative containing three toxic metals — inorganic arsenic, hexavalent chromium (Cr(VI)), and copper — that was used extensively from the 1940s through 2003 for outdoor wood rot resistance. CCA-treated wood is visually distinctive: a greenish-gray tint imparted by the copper chromate preservative. The wood preservative works by incorporating the toxic metals into the wood structure at levels lethal to wood-rot fungi and insects. These same metals, however, present human health hazards through the surface of the treated wood, which continues to leach arsenic via rainfall and physical contact for decades after treatment. EPA negotiated a voluntary phase-out agreement with CCA wood manufacturers effective December 31, 2003 — CCA-treated wood was withdrawn from the residential-use market for applications including playground equipment, picnic tables, boat docks, decks, and fences in public-accessible areas. CCA treatment remains permitted for industrial applications: highway utility poles, marine pilings, and industrial structures. The legacy problem is substantial: millions of CCA-treated playground structures and residential decks installed before January 2004 remain in service, leaching arsenic from their surfaces and into the surrounding soil. Children's exposure occurs through two primary pathways: hand-to-mouth transfer (hands contact the wood surface, arsenic transfers to hands, child puts hands in mouth — the same pathway documented for lead paint); and incidental soil ingestion (soil beneath CCA structures is arsenic-enriched, and children playing in or near this soil ingest it). Studies measuring urinary arsenic in children who regularly use CCA playground equipment versus children using alternative-material equipment have documented elevated urinary arsenic in the CCA-exposed group. Annual application of oil-based penetrating sealers to CCA wood surfaces substantially reduces arsenic surface transfer and is the practical mitigation for legacy structures not yet replaced.","synthesis":{"derived_risk_level":"high","synthesis_confidence":0.878,"synthesis_method":"compound_composition","context_used":"human_child","context_source":"product_users","exposure_modifier":1.2,"vulnerability_escalated":true,"escalation_reason":"Child exposure group","compounds_resolved":2,"compounds_total":2,"synthesis_date":"2026-03-27","synthesis_version":"1.0.0"},"hazard_summary":{"sensitive_populations":"child","overall_risk":"high","primary_concerns":["Carcinogenicity concern (high): Arsenic CCA wood contains chromium in two principal oxidation states: Cr(VI) (chromate) in fresh treatment solution, which reduces to Cr(III) over time as the chromate reacts with wood components during fi..."],"exposure_routes":"ingestion, skin contact"},"exposure":{"routes":["dermal"],"contact_types":["ingestion","dermal"],"users":["child","toddler","adult"],"duration":"chronic","frequency":"regular","scenarios":["Incidental mouthing or hand-to-mouth transfer by children"],"notes":"Children's exposure pathways from CCA playground equipment and decks: (1) Hand-to-mouth — child touches CCA wood surface (climbing bars, deck boards, sandbox frame), arsenic transfers to hands, child puts hands in mouth during or after play; transfer rate documented in surface wipe studies correlating with urinary arsenic elevation; (2) Incidental soil ingestion — soil beneath and around CCA structures is arsenic-enriched; children playing in soil in this zone ingest arsenic-bearing soil; sandbox soil beneath CCA frames is the highest-risk soil ingestion scenario because children directly play in the sand/soil; (3) Dermal absorption through intact skin — arsenic has limited dermal absorption through intact skin but enhanced absorption through minor cuts, eczema, and dermal breaches typical in active children; (4) Adult exposures: DIY deck builders sawing CCA lumber (without respiratory protection) inhale arsenic-chromium sawdust — occupational-level acute exposure; summer deck cooking/dining (adults eating on CCA deck surfaces where arsenic residue may contact food). Frequency: daily or frequent use of CCA playground equipment during childhood represents the key chronic exposure."},"consumer_guidance":{"red_flags":[{"indicator":"Playground equipment or residential deck with greenish-gray wood tint — installed before 2004 and not yet replaced or sealed; sandbox with a CCA-wood frame; CCA deck adjacent to vegetable garden (arsenic leaches into adjacent soil)","meaning":"The greenish-gray tint of CCA-treated wood is the primary visual indicator of CCA treatment. All outdoor wood structures with this tint installed before 2004 should be presumed CCA unless documented otherwise. Sandboxes with CCA wood frames create a direct child-soil-ingestion pathway: the arsenic-enriched sand/soil inside the CCA frame is what children play in and inevitably ingest. CCA decks adjacent to vegetable gardens leach arsenic into garden soil — vegetables grown in arsenic-contaminated soil take up arsenic into the edible portions (leafy vegetables and root vegetables are highest risk).","action":"Test the soil adjacent to suspected CCA structures: state cooperative extension offices and private environmental labs offer soil arsenic testing for ~$20–50 per sample; send soil from directly below CCA play surfaces and within the sandbox frame. If CCA is confirmed: short-term mitigation — apply oil-based penetrating sealer (Thompsons WaterSeal, Cabot Australian Timber Oil, similar) to all accessible CCA surfaces; reseal annually; prevents children from accessing CCA-treated areas immediately after rain (when surface arsenic concentrations are highest from fresh leaching). Long-term solution: replace CCA structures with ACQ, CA-B, or composite lumber. If replacement is not immediately feasible: limit children's play time on CCA structures; have children wash hands immediately after touching CCA wood or playing in adjacent soil; do not allow sandbox use in a CCA-framed sandbox."},{"indicator":"Burning CCA wood — indoor fireplace, outdoor fire pit, waste burning, or BBQ with CCA scraps","meaning":"CCA wood combustion concentrates arsenic and chromium in smoke and ash at toxic levels — arsenic in CCA wood ash can reach several percent by weight; burning CCA wood releases arsenic-laden smoke that is acutely toxic at higher levels and carcinogenic at lower chronic levels. CCA wood should NEVER be burned: not in fireplaces, not in wood stoves, not in outdoor fire pits, not in barrel burners, not as charcoal starter. This is widely unknown by homeowners who may burn scrap deck boards or dismantled CCA playground structures. EPA explicitly prohibits burning of CCA-treated wood in open burning and restricts it in permitted burn facilities.","action":"Dispose of CCA wood scrap through permitted construction and demolition waste facilities or hazardous waste disposal — call your county solid waste authority for CCA wood disposal guidance. Never burn CCA wood in any residential combustion device. If CCA wood ash has been produced from accidental burning: treat the ash as hazardous waste; do not use CCA wood ash as a garden fertilizer (which is sometimes done with regular wood ash)."}],"green_flags":[{"indicator":"Playground equipment and decks confirmed as post-2003 installation using ACQ, CA-B, or composite lumber; CCA structures that have been professionally sealed with oil-based penetrating sealer within the past year; soil testing below EPA residential soil arsenic standard (0.39 mg/kg in highly sensitive areas, typically <10 mg/kg regional background) under play areas","meaning":"Post-2003 pressure-treated wood for residential use is ACQ or CA-B — no arsenic, dramatically lower human toxicity. Composite lumber is completely inert with respect to heavy metal leaching. Annual oil-based penetrating sealer on CCA structures has been documented in EPA SFIREG studies to substantially reduce arsenic surface transfer to wipe tests — sealing is meaningful mitigation for legacy structures not yet replaced. Soil arsenic testing below background levels confirms the soil under play areas has not been contaminated by CCA leaching.","verification":"Identify wood treatment type: newer pressure-treated wood (post-2003 residential) should be marked with a preservative retention stamp on the wood end — look for 'ACQ,' 'CA-B,' or 'Cu-B' markings; CCA wood may be marked 'CCA' or simply show the greenish tint. Ask the deck or playground installer for product documentation — reputable installers will have records of the lumber type and treatment. Soil testing: state cooperative extension offices, local environmental labs. EPA SFIREG arsenic wipe study results available at EPA arsenic in wood page."}],"what_to_ask":[{"question":"When was this playground equipment or deck installed, and what preservative treatment was used? Does the wood have a greenish-gray tint suggesting CCA treatment? Has the soil beneath the play equipment been tested for arsenic? Has the structure been sealed with an oil-based penetrating sealer within the past year? Are there plans to replace CCA structures with post-2003 alternative treatments?","why_it_matters":"CCA-treated playground equipment installed before 2004 remains in service at schools, parks, and residential properties across the United States. The arsenic in that wood continues to leach to surfaces where children touch it and to soil where children play. Unlike paint lead hazard — which triggered mandatory abatement programs — CCA playground equipment has no federal mandatory replacement or remediation program; it remains on the property owner and jurisdiction to manage. Urinary arsenic elevation in children using CCA playgrounds has been documented in peer-reviewed research; it correlates with frequency of use. The mitigation is available, affordable, and effective: annual sealer application costs under $50 and reduces surface arsenic transfer substantially.","good_answer":"Playground equipment confirmed post-2003 ACQ or composite material; deck built post-2004 with ACQ lumber and marked as such; soil testing completed with results below background arsenic levels; no CCA structures in regular use by children; if CCA confirmed, annual sealer applied and children wash hands after contact.","bad_answer":"Greenish-gray playground equipment with no installation date records; no soil testing under play areas; sandbox with CCA wood frame where children play daily; CCA deck used for vegetable gardening adjacent area; deck with unknown installation date in pre-2004 range with no assessment performed."}],"alternatives":[{"name":"ACQ or Copper Azole treated lumber","notes":"Safer arsenic-free preservative options approved for playground use"},{"name":"Naturally rot-resistant wood (cedar, redwood, composite)","notes":"No chemical preservatives; suitable for decks and landscape applications"},{"name":"Composite decking materials","notes":"Made from recycled plastic/wood fiber; durable without toxic preservatives"}],"notes":null},"regulatory":{"applicable_regulations":[{"jurisdiction":"US","regulation":"EPA — Voluntary cancellation of CCA registrations for residential uses, effective December 31, 2003; CCA remaining registered for industrial/commercial applications; EPA SFIREG arsenic exposure mitigation studies for CCA wood","citation":null,"requirements":"EPA 2003 voluntary cancellation: negotiated with CCA manufacturers (Arch Wood Protection, Chemical Specialties Inc., Osmose Wood Preserving) to cancel EPA pesticide registrations for CCA treatment for residential end-use applications effective December 31, 2003; covered playground equipment, decks, picnic tables, fencing, boat docks, and similar public-accessible residential structures. CCA treatment remains registered for: highway utility poles, marine pilings, industrial building materials, railroad ties, and other commercial/industrial applications not accessible to the general public as a residence. EPA SFIREG (State FIFRA Issues Research and Evaluation Group): conducted studies evaluating arsenic transfer from CCA wood surfaces and arsenic in soil under CCA structures; evaluated sealer effectiveness; results publicly available. No mandatory recall of existing CCA structures — the phase-out was prospective (new manufacture stopped); existing structures remain in service.","compliance_status":null,"effective_date":null,"enforcing_agency":null,"penalties":null,"source_ref":"src_002"},{"jurisdiction":"US","regulation":"EPA — burning CCA wood prohibited; EPA guidance on CCA wood disposal through construction and demolition (C&D) waste streams","citation":null,"requirements":"EPA Open Burning Rule: open burning of CCA-treated wood is prohibited. Permitted incinerators must meet specific emission standards if accepting CCA wood. Household disposal: EPA recommends disposal of CCA wood as solid waste at C&D facilities or hazardous waste facilities accepting treated wood — specific acceptance varies by state. Do not reuse or repurpose CCA wood in any application where human contact is expected, including garden planters, raised vegetable garden beds, or indoor furniture.","compliance_status":null,"effective_date":null,"enforcing_agency":null,"penalties":null,"source_ref":"src_003"}],"certifications":[{"name":"CPSIA (if children's)","issuer":"CPSC","standard":"Consumer Product Safety Improvement Act","scope":"Lead, phthalate content limits if classified as children's product"}],"labeling":{"required_disclosures":[],"prop65_warning":{"required":null,"chemicals":[],"endpoint":null,"notes":null},"ghs_labeling":{"required":null,"signal_word":null,"pictograms":[],"hazard_statements":[],"notes":null},"hidden_ingredients":{"trade_secret_protected":null,"categories_hidden":[],"estimated_count":null,"known_concerns":null,"notes":null},"notes":null},"recalls":[],"regulatory_gap":null,"notes":null},"lifecycle":{"recyclable":false,"disposal_guidance":"Varies by material; PVC items should not be burned; donate if reusable","hazardous_waste":false,"expected_lifespan":"1-3_years"},"formulation":{"form":"composite_material","key_ingredients":[{"hq_id":null,"name":"Wood (softwood: pine, fir, spruce)","role":"base_material","concentration_pct":"90-98"},{"hq_id":null,"name":"Copper-based or arsenic-based preservative","role":"additive","concentration_pct":"0.5-2"},{"hq_id":null,"name":"Water carrier","role":"solvent","concentration_pct":"1-5"}],"certifications":[]},"materials":{"common":[{"material_id":"hq-m-str-000042","material_name":"Inorganic arsenic — the primary human health concern in CCA-treated wood; applied to wood at 0.25–2.5 pounds of arsenic trioxide per cubic foot of treated wood; continues to leach from wood surface for decades","component":"wood preservative component in CCA-treated lumber; applied at high concentrations to penetrate wood fibers; leaches from wood surface via rain, physical contact, and weathering","prevalence":"universal in all CCA-treated lumber; estimated 5 billion board feet of CCA lumber used in residential applications before 2004 phase-out; millions of CCA playground structures and decks remain in service nationwide","notes":"CCA formulation: original CCA-C formulation (most common residential grade): arsenic pentoxide 47.5%, chromium trioxide 18.5%, copper oxide 34.0% (by active ingredient weight); applied under pressure to penetrate wood fibers at preservative retention levels of 0.25–0.40 lb/ft³ for above-ground uses (decks, fences) to 0.60–2.50 lb/ft³ for ground-contact uses (landscape timbers, poles). Arsenic leaching dynamics: CCA wood leaches arsenic via rainfall and surface contact continuously after installation; leaching rate decreases with weathering age but does not reach zero for decades; surface wipe studies on CCA playground equipment found arsenic transferable from wood surface to skin-equivalent wipes at concentrations correlating with urinary arsenic elevation in children. Soil arsenic accumulation: EPA studies found soil beneath CCA playground equipment (within 6 feet of treated posts and horizontal surfaces) had arsenic concentrations 5–200× background levels; sandbox soil beneath CCA structures specifically dangerous because of direct child-soil-mouth contact. Inorganic arsenic health effects: IARC Group 1 human carcinogen (lung, bladder, skin cancers); skin keratosis; peripheral neuropathy; developmental neurotoxicity in children at chronic low-level exposure.","_note_crossref_fix":"Was hq-c-ino-000002 — compound ref moved to compound_composition","hq_id":"hq-m-str-000042"}],"concerning":[{"material_id":null,"material_name":"Hexavalent chromium (Cr(VI)) — component of CCA preservative; present in freshly treated CCA wood at higher concentration; reduces to Cr(III) over time on wood surface but Cr(VI) may persist in leachate","concern":"CCA wood contains chromium in two principal oxidation states: Cr(VI) (chromate) in fresh treatment solution, which reduces to Cr(III) over time as the chromate reacts with wood components during fixation process. However, Cr(VI) may persist in leachate from CCA wood, particularly in runoff water from freshly cut or newly installed CCA wood. Cr(VI) is an IARC Group 1 human carcinogen (established occupational carcinogen at inhalation — lung cancer; dermal contact causes ulceration and sensitization). Cutting and sawing CCA wood releases arsenic- and chromium-containing sawdust — an occupational exposure hazard for workers and a household hazard for DIY deck builders who saw CCA lumber without respiratory protection. EPA guidance: do not burn CCA wood indoors or outdoors — combustion concentrates arsenic and chromium in ash and smoke at toxic levels. No standalone hq-c ID for chromium — documented in CCA wood context here; cross-reference to hq-p-out-000007 chromium discussion in hq-p-chd-000017 (children's cosmetics Cr(VI) context).","compounds_of_concern":["hq-c-ino-000002"],"source_refs":["src_001","src_002"]}],"preferred":[{"material_id":"hq-m-str-000042","material_name":"ACQ (alkaline copper quaternary), CA-B (copper azole Type B), or borate-treated wood for outdoor structural use; composite lumber (Trex, TimberTech); naturally rot-resistant hardwoods (ipe, black locust, cedar)","why_preferred":"Post-2003 replacement wood preservatives for residential outdoor use: ACQ (alkaline copper quaternary) and CA-B (copper azole Type B) contain copper and quaternary ammonium compounds or azole fungicides — no arsenic, no chromium, substantially lower human toxicity than CCA. These treatments are functionally equivalent to CCA for rot and insect resistance in above-ground and ground-contact applications and are approved for all the residential uses from which CCA was withdrawn. Borate-treated wood: sodium borate or disodium octaborate tetrahydrate treatment; effective for above-ground applications; very low mammalian toxicity; not suitable for ground contact or high moisture environments. Composite lumber (Trex, TimberTech, Fiberon): wood-plastic composite or all-plastic lumber — no preservative treatment needed; durable, low-maintenance; no leaching of toxic metals; more expensive than treated wood initially but lower lifetime maintenance cost. Cedar, redwood, black locust, ipe: naturally rot-resistant heartwood; no chemical preservative treatment needed for above-ground outdoor use; ipe and black locust highly durable for ground-contact applications; highest cost option but eliminates preservative chemistry entirely.","tradeoffs":"ACQ and CA-B: higher copper content than CCA can corrode some metals (galvanized nails, aluminum hardware) — hot-dip galvanized or stainless steel fasteners required; verify hardware compatibility. Composite lumber: higher upfront cost than pressure-treated wood; some early-generation composites (pre-2010) had issues with mold on the surface; newer generation products much improved. Cedar and redwood: sustainable sourcing concerns; ipe requires FSC certification to avoid illegal deforestation. The arsenic-free alternatives are more expensive at purchase; the arsenic cost of legacy CCA structures has been borne by communities through decades of childhood arsenic exposure.","hq_id":"hq-m-str-000042"}]},"compound_composition":[{"hq_id":"hq-c-ino-000002","compound_name":"Arsenic (inorganic)","role":"compound_of_concern","typical_concentration":null},{"hq_id":"hq-c-org-002023","compound_name":null,"role":null,"typical_concentration":null}],"identifiers":{"common_names":["pressure-treated lumber and cca wood","pressure-treated lumber","cca wood"],"aliases":[],"manufacturer":null,"brands":[]},"brand_examples":[{"brand":"Generic Mass-Market Brand A","manufacturer":"Consumer Products Corporation","market_position":"mass_market","notable":"Widely available mass-market option"},{"brand":"Generic Mass-Market Brand B","manufacturer":"Consumer Goods Ltd","market_position":"mass_market","notable":"Popular budget alternative"},{"brand":"Premium Brand A","manufacturer":"Premium Consumer Inc","market_position":"premium","notable":"Upscale premium positioning"},{"brand":"Professional Brand","manufacturer":"Professional Products Co","market_position":"professional","notable":"Professional/salon-grade option"},{"brand":"Specialty Eco-Brand","manufacturer":"Natural Products Ltd","market_position":"premium","notable":"Sustainable/natural product line"}],"sources":[{"id":"src_001","type":"epidemiological","title":"Kwon E et al. — 'Urinary arsenic concentrations in 4–6 year-old children and assessing the potential role of CCA-treated wood playsets and other environmental variables.' Science of the Total Environment (2004); EPA CCA arsenic wipe study results","url":"https://doi.org/10.1016/j.scitotenv.2003.11.032","accessed":"2026-03-08","year":2004,"notes":"Urinary arsenic in children and CCA playground use: measured urinary arsenic in 4–6 year-old children with and without CCA playground exposure; found statistically significant elevation in children with regular CCA playground access; urinary arsenic correlated with frequency of playset use and whether hands were washed after use. EPA SFIREG wipe study: arsenic transferable from CCA wood surface to simulated skin wipes at concentrations representing meaningful ingestion dose for young children (hand-to-mouth behavior); sealer application reduced wipe arsenic by 60–90% in SFIREG studies. Soil contamination: arsenic concentrations in soil directly under CCA playground equipment posts and surfaces documented at 5–200× background in multiple studies."},{"id":"src_002","type":"regulatory","title":"EPA — 'Chromated Copper Arsenate (CCA)' pesticide registration review; EPA voluntary cancellation notice for CCA residential uses (2003); EPA consumer guidance on CCA wood","url":"https://www.epa.gov/ingredients-used-pesticide-products/chromated-arsenicals","accessed":"2026-03-08","year":2003,"notes":"EPA CCA voluntary cancellation: effective December 31, 2003; covers CCA-A and CCA-C formulations for residential end-use applications; CCA manufacturers agreed to stop producing CCA for residential use; transition products are ACQ (alkaline copper quaternary), CA-B (copper azole Type B), and MCQ (micronized copper quaternary) — all arsenic-free and chromium-free. Arsenic retention in CCA wood: 0.25–0.40 lb/ft³ for above-ground residential (decks); 0.40 lb/ft³ for ground-contact (landscape timbers); approximately 0.25 lb of arsenic per cubic foot of treated wood — a typical residential deck of 500 ft² contains pounds of arsenic in the lumber. EPA provided transition guidance to consumers including sealer recommendations for legacy CCA structures."},{"id":"src_003","type":"regulatory_guidance","title":"EPA — 'Consumer Information about Treated Wood' (2022 guidance update); EPA guidance on CCA wood disposal; EPA SFIREG Working Group arsenic exposure reduction study (2008)","url":"https://www.epa.gov/ingredients-used-pesticide-products/consumer-information-about-treated-wood","accessed":"2026-03-08","year":2022,"notes":"EPA consumer guidance: provides visual identification guidance for CCA wood (greenish-gray color); recommends oil-based penetrating sealer application to reduce arsenic surface transfer; recommends handwashing after contact with CCA wood or adjacent soil; advises against CCA wood in raised vegetable gardens; recommends replacement as long-term solution. SFIREG 2008 study: documented 60–90% reduction in arsenic surface wipe transfer following application of oil-based penetrating sealers to CCA wood; sealers must be re-applied annually to maintain effectiveness. Disposal guidance: CCA wood should not be burned; contact local C&D waste authority or hazardous waste facility for disposal."}],"meta":{"schema_version":"4.0.0","last_updated":"2026-03-25","timestamp":"2026-05-01T14:28:07.228Z"}}