{"hq_id":"hq-p-hom-000279","name":"Ceramic Glaze for Pottery (Lead and Cadmium in Traditional Glazes, Leaching into Food, FDA CPG 545.450)","category":{"primary":"home_art","secondary":"ceramic_glaze","tags":["ceramic","glaze","pottery","lead","cadmium","leaching","food contact","dinnerware","FDA","kiln","earthenware","stoneware"]},"product_tier":"HOM","overall_risk_level":"high","description":"Ceramic glazes used in pottery and ceramics may contain lead oxide (PbO, used as a flux to lower melting temperature and increase gloss) and cadmium compounds (CdS, CdSe for bright yellow, orange, and red colors) that leach from fired surfaces into food and beverages, particularly acidic liquids (coffee, wine, tomato sauce, citrus juice). Lead-glazed pottery is one of the oldest and most persistent sources of lead poisoning globally — the CDC estimates that lead-glazed ceramics are the leading source of lead exposure in Mexico and several Latin American countries, and imported hand-crafted pottery remains a significant lead exposure source for US families. FDA Compliance Policy Guide 545.450 sets action levels for lead and cadmium leaching from ceramics: flatware ≤3.0 ppm lead, cups/mugs ≤0.5 ppm lead, and large hollowware ≤1.0 ppm lead (using 4% acetic acid extraction). Hobby potters firing lead-based glazes face both inhalation exposure to lead fumes during kiln firing (lead volatilizes above 1000C) and the risk of creating leachable lead dinnerware for family use. Commercial food-service ceramics are generally compliant, but hand-made, antique, imported, and hobby-fired pieces frequently exceed FDA action levels by 10-1000x.","synthesis":{"derived_risk_level":"high","synthesis_confidence":0.744,"synthesis_method":"compound_composition","context_used":"human_child","context_source":"product_users","exposure_modifier":1.15,"vulnerability_escalated":true,"escalation_reason":"Child exposure group","compounds_resolved":2,"compounds_total":2,"synthesis_date":"2026-05-09","synthesis_version":"1.2.0","methodology_note":"exposure_modifier and adjusted_magnitude are computed from ALETHEIA-calibrated heuristics (route × duration × frequency multipliers, clamped to [0.5, 1.4]). Multipliers are directionally informed by EPA Exposure Factors Handbook (2011) and CalEPA OEHHA but are not regulatory consensus. See /api/methodology for full disclosure."},"hazard_summary":{"sensitive_populations":"children (50% lead GI absorption vs 10% adult), pregnant women (lead crosses placenta, causes fetal neurodevelopmental damage), families using imported hand-crafted pottery, hobby potters firing lead glazes","overall_risk":"high","primary_concerns":["Lead-glazed pottery is the leading lead exposure source in several countries — imported pieces frequently exceed FDA limits by 10-1000x","Acidic beverages (coffee, wine, citrus, tomato) dramatically accelerate lead leaching from glazed surfaces","Hobby potters inhale lead fumes during kiln firing and create potentially hazardous dinnerware","Cadmium in red/orange/yellow glazes: IARC Group 1 carcinogen, leaches alongside lead"],"exposure_routes":"Ingestion (primary — lead and cadmium leaching from glaze into food/beverage, especially acidic liquids). Inhalation (kiln firing volatilizes lead above 1000C — potter exposure)."},"exposure":{"routes":["ingestion","inhalation"],"contact_types":["ingestion_food_contact","inhalation_kiln_firing"],"users":["adult","child","hobbyist"],"duration":"chronic","frequency":"daily","scenarios":["Family uses imported hand-crafted lead-glazed pottery for daily coffee — chronic lead ingestion from acidic beverage leaching","Hobby potter fires lead-based glaze at high temperature — inhales lead fumes from kiln","Child eats from antique or handmade bowl with lead glaze — higher GI absorption (50%) than adult","Tourist purchases decorative pottery in Mexico/Central America, uses for food service — lead leaching far exceeding FDA limits"],"notes":"Lead in ceramic glazes: PbO is a powerful flux lowering glaze melting point by 100-200C and producing high gloss. Properly formulated and fired lead glazes CAN be food-safe (lead fritted into glaze matrix at correct temperature), but underfiring, incorrect formulation, or thermal shock creates leachable lead. FDA CPG 545.450: 4% acetic acid extraction test, 24-hour soak. Action levels: flatware ≤3.0 ppm Pb, cups/mugs ≤0.5 ppm Pb, large hollowware ≤1.0 ppm Pb, small hollowware ≤2.0 ppm Pb. Cadmium: ≤0.25 ppm cups, ≤0.5 ppm flatware. California Prop 65: more stringent. Mexican lead-glazed pottery (barro vidriado): CDC and WHO identify as leading Pb exposure source in Latin America."},"consumer_guidance":{"usage_warning":"NEVER use hand-crafted, imported, antique, or unverified pottery for food or beverage service unless it has been tested for lead and cadmium leaching by an accredited laboratory. Decorative pottery (especially from Mexico, Central America, Italy, Portugal) should be used for decoration ONLY — not food. Home lead test kits are NOT reliable for ceramics — they only detect surface lead, not leachable lead. If you are a hobby potter, use lead-free glazes exclusively for any functional ware. Commercial food-service ceramics from major manufacturers are generally compliant with FDA action levels.","safer_alternatives":["Lead-free ceramic glazes (boron, lithium, zinc flux systems)","Stoneware fired to cone 6+ (higher temperatures reduce leaching even from lead glazes, but lead-free is always safer)","Commercial dinnerware from established manufacturers with FDA compliance documentation","Glass, stainless steel, or food-grade silicone for acidic food/beverage storage"]},"regulatory":{"applicable_regulations":[{"jurisdiction":"USA","regulation":"FDA Compliance Policy Guide 545.450 — Lead and Cadmium in Ceramics","citation":"FDA CPG Section 545.450 (Pottery/Ceramics — Lead and Cadmium Content); 21 CFR 109.16 (unavoidable contaminants)","requirements":"FDA sets action levels for lead and cadmium extractable from ceramic food-contact articles using 4% acetic acid, 24-hour, room temperature leach test. Flatware: ≤3.0 ppm Pb, ≤0.5 ppm Cd. Cups/mugs: ≤0.5 ppm Pb, ≤0.25 ppm Cd. Large hollowware: ≤1.0 ppm Pb, ≤0.5 ppm Cd. Small hollowware: ≤2.0 ppm Pb, ≤0.5 ppm Cd. FDA can detain and refuse entry of imported ceramics exceeding these levels. California Proposition 65 imposes more stringent requirements.","compliance_status":null,"effective_date":null,"enforcing_agency":"FDA Center for Food Safety and Applied Nutrition; CBP (import enforcement)","penalties":null,"source_ref":null}],"certifications":[],"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":"Dispose of suspected lead-glazed pottery in regular trash — do not donate for food use. Broken pottery shards may be used for drainage in non-food garden applications.","hazardous_waste":false,"expected_lifespan":"Centuries for intact fired ceramics; glaze degradation (crazing, chipping) increases leaching over time"},"formulation":{"form":"varies","key_ingredients":[],"certifications":[]},"materials":{"common":[],"concerning":[],"preferred":[]},"compound_composition":[{"hq_id":"hq-c-ino-000001","compound_name":null,"role":"glaze_flux","typical_concentration":"lead oxide (PbO) in traditional glazes: 20-60% of glaze formula; leaches into acidic food/beverage; FDA action level 0.5 ppm for cups, 3.0 ppm for flatware"},{"hq_id":"hq-c-ino-000005","compound_name":null,"role":"colorant","typical_concentration":"cadmium sulfide/selenide for yellow/orange/red; FDA action level 0.25 ppm for cups; IARC Group 1 carcinogen (inhalation)"}],"identifiers":{"common_names":["ceramic glaze for pottery (lead and cadmium in traditional glazes, leaching into food, fda cpg 545.450)"],"aliases":[],"manufacturer":null,"brands":[]},"brand_examples":[],"brand_examples_disclaimer":null,"sources":[{"type":"expert_curation","name":"ALETHEIA Safety Database","date":"2026-03-26"}],"meta":{"schema_version":"4.0.0","last_updated":"2026-03-26","timestamp":"2026-05-14T01:32:57.018Z"}}