Agency for Toxic Substances and Disease Registry (ATSDR)
Toxicological Profile for Toluene Diisocyanate and Methylenediphenyl Diisocyanate
ATSDR Toxicological Profile
TDI vs MDI Polyurethane Foam Off-Gassing Smell
Comparative analysis of Toluene Diisocyanate (TDI) vs Methylene Diphenyl Diisocyanate (MDI) in memory foam off-gassing.
MDI Has Lower Off-Gassing
Direct answer summary
Toluene diisocyanate (TDI) and methylene diphenyl diisocyanate (MDI) are primary chemical precursors used to synthesize polyurethane foams. TDI has a higher vapor pressure, resulting in a stronger, sharper chemical odor and higher initial off-gassing of volatile organic compounds (VOCs). MDI has a significantly lower vapor pressure, produces less volatile emissions during curing, and is increasingly preferred by premium foam manufacturers seeking CertiPUR-US compliance.
Key points
TDI has high volatility, leading to the familiar pungent 'new mattress' off-gassing smell.
MDI features lower vapor pressure and produces significantly fewer airborne chemical emissions.
Both react fully during proper curing; lingering odors indicate rushed manufacturing or incomplete degassing.
Interactive example
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Verified Law Label
Interactive Visual Tool
Law Label & Material Audit
Inspect the physical law label tag, decode the state Uniform Registry Number (URN), and review certified material percentages under CPSC 16 CFR Part 1633.
What the law tag tells you
Uniform Law Label & Material Deconstruction
Under FTC 16 CFR Part 303 and IABFLO uniform law label standards, bedding manufacturers must disclose exact net filling weights using standardized generic fiber terms. Marketing buzzwords are prohibited under federal penalty.
▲ Sewn Into Seam (Tyvek Substrate) ▲
UNDER PENALTY OF LAW THIS TAG NOT TO BE REMOVED EXCEPT BY THE CONSUMER
ALL NEW MATERIAL CONSISTING OF
POLYURETHANE FOAM PAD55%
RESIN-TREATED COTTON BATTING25%
RAYON FIBER / WOOL CHAR BARRIER20%
Net Filling Weight (Excluding Steel Springs)
Uniform Registry Number (Click to decode)
REG. NO. UT-12345 (FL)
Certification is made by the manufacturer that the materials in this article are described in accordance with law.
Manufacture Date:04/2026
Plant Facility:Tampa, FL
Legal Entity:Saatva Inc. / Bedding Industries of America (BIA)
16 CFR Part 1633 Prototype: STV-115-HYB-2026Inspect →
Physical Tag Dimensions: 2.75" × 3.75" (Meets IABFLO 2.5" × 3.0" min)
What the tag number means
REG. NO. UT-12345 (FL)
Issuing State
UT (Utah)
Registry Sequence
#12345
Plant Location
FL (Florida)
IABFLO 31-State Reciprocity: The issuing state (UT) participates in the Uniform Law Label system. This single registration permits lawful commercial distribution across all 31 regulated US bedding jurisdictions without duplicate state tags.
Specifications
Recorded specifications
Values and benchmarks recorded for this question.
| Specification | Measured value | Benchmark | Status |
|---|---|---|---|
| TDI Vapor Pressure | 0.01 mmHg at 25°C (High Volatility) | Higher Off-Gassing Potential | warning |
| MDI Vapor Pressure | 0.000005 mmHg at 25°C (Ultra-Low) | Minimal Ambient Volatility | pass |
| CertiPUR-US Limit | Unreacted Isocyanates < Detection Limit | Complete Polymerization | pass |
| Curing Degassing Standard | 48 - 72 Hour Curing Chamber Hold | Mandatory Factory Degassing | pass |
Standards reference: Benchmarks derived from ASTM D3574 (flexible cellular foam), CPSC 16 CFR 1633 (open flame flammability), and clinical capillary closing thresholds (32.0 mmHg).
Checklist
Consumer Safety & Chemical Verification Protocol
Step-by-step physical inspection procedure for flame barrier integrity and law label compliance.
- 01
Check Foam Certifications
Verify that all polyurethane foams carry active CertiPUR-US or GREENGUARD Gold seals.
Watch for: Never sleep in an unventilated room with a freshly unboxed memory foam mattress.
- 02
Ventilate New Bed
Allow compressed memory foam mattresses to expand in a well-ventilated room with open windows for 72 hours.
Watch for: Avoid running heaters directly on freshly unboxed foam; heat accelerates VOC release.
- 03
Evaluate Odor Decay
Ensure the chemical odor diminishes substantially within 3 to 7 days.
Watch for: If strong solvent smells persist after 14 days, file a defect claim with the brand.
Sources
Sources for this answer
Read the source documents behind the thresholds, measurements, and policy details used here.
View source
Alliance for Flexible Polyurethane Foam
CertiPUR-US Technical Guidelines for Polyurethane Foam
CertiPUR-US Standard