CarCareTruth Score
Decent, but wear gloves and ventilate.
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Prices may varyThe manufacturer's Safety Data Sheet classifies this product with one or more GHS Category 1 health hazards — the most severe tier. The hazard statements in quotes below are the verbatim GHS language from the SDS, as required by OSHA's Hazard Communication Standard. The line under each statement translates the GHS classification into plain language.
GHS Category 1 reproductive toxicity — classified as suspected of damaging fertility or harming an unborn child.
If swallowed, inhaled, or splashed in eyes:
Call Poison Control immediately at 1-800-222-1222 (US, 24/7, free) and have the product container with you. Poison Control's standing guidance is to not induce vomiting after chemical exposure; they will direct first-aid steps based on the specific product.
About this product's hazards. This product's Safety Data Sheet uses signal word danger. Read the manufacturer's SDS and follow all safety instructions before use. CarCareTruth ratings translate the manufacturer's safety sheet. They do not replace the SDS or substitute for a hazard assessment specific to your task.
Health score is for adult use as intended, per the manufacturer's SDS. It does not model child ingestion, accidental spill cleanup, or off-label use. See the safety panel below for full hazard classification, and /disclaimer for the full editorial scope.
GHS hazard codes are quoted from the manufacturer’s Safety Data Sheet. PPE tiers below translate those codes and the listed ingredient chemistry; they are not CarCareTruth recommendations.
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From the manufacturer’s Safety Data Sheet, Section 8
“SDS §8 specifies full face shield and indirect vented goggles. H319 (eye irritation Cat 2) at SDS §2 is the driving code; the current PPE escalation table reserves required tier for H318 (serious eye damage Cat 1), which is not present here, so recommended is the correct tier.”
— 3M
U.S. regulatory standard
29 CFR 1910.133(a)(1)
“The employer shall ensure that each affected employee uses appropriate eye or face protection when exposed to eye or face hazards from… liquid chemicals…”
ANSI Z87.1 (incorporated via §1910.6)
OSHA standards apply to workplaces. Cited here as the U.S. reference threshold for the underlying hazard class.
CarCareTruth publishes the cited sources verbatim and does not advise what action a user should take. Consult the full SDS before use.
From the manufacturer’s Safety Data Sheet, Section 8
“SDS §8 specifies polymer laminate gloves (nitrile for incidental contact). H315 (skin irritation Cat 2) at SDS §2 is the driving code; the current PPE escalation table reserves required tier for H314 (corrosion) or H317 (sensitizer), neither of which is present here, so recommended is the correct tier.”
— 3M
U.S. regulatory standard
29 CFR 1910.138(a)
“appropriate hand protection when employees' hands are exposed to hazards such as those from… chemicals which produce an adverse effect on the skin or eyes…”
OSHA standards apply to workplaces. Cited here as the U.S. reference threshold for the underlying hazard class.
CarCareTruth publishes the cited sources verbatim and does not advise what action a user should take. Consult the full SDS before use.
From the manufacturer’s Safety Data Sheet, Section 8
“SDS §8 specifies a half facepiece or full facepiece supplied-air respirator. The DANGER signal word is driven by H360 (Reproductive Toxicity Cat 1) and H370 (STOT-SE Cat 1, cardiovascular) at mixture level per SDS §2; overhead aerosol application in a semi-enclosed garage is the primary exposure scenario.”
— 3M
U.S. regulatory standard
29 CFR 1910.134; 1910.138; 1910.1000
“the primary objective shall be to prevent atmospheric contamination… When effective engineering controls are not feasible… appropriate respirators shall be used.”
OSHA standards apply to workplaces. Cited here as the U.S. reference threshold for the underlying hazard class.
CarCareTruth publishes the cited sources verbatim and does not advise what action a user should take. Consult the full SDS before use.
The published Safety Data Sheet for this product does not specify ventilation protection for consumer use.
Workplace context
29 CFR 1910.134(a); 1910.1000
“the primary objective shall be to prevent atmospheric contamination [via] accepted engineering control measures (for example, enclosure or confinement of the operation, general and local ventilation…).”
Triggered by GHS H336 on the SDS.
OSHA standards apply to workplaces. Cited here as the U.S. reference threshold for the underlying hazard class.
PPE tiers translate the manufacturer’s SDS and U.S. regulatory standards. Not professional safety advice. How we report safety.
This product ranks #3 of 6 in Undercoating.
Last reviewed July 5, 2026
TL;DR Premium rubberized asphalt undercoating with manufacturer-documented 500-hour salt spray and water immersion resistance; the aerosol wand handles overhead frame-rail application, though the community track record is still thin. The SDS carries a DANGER signal word; required-tier respiratory protection is needed for overhead aerosol use.
A petroleum-based rubberized asphalt aerosol leaving a corrosion barrier, road-noise dampening, and a moisture seal on frame rails, seams, and wheel wells. The 3M TDS documents excellent adhesion after two days, excellent abrasion resistance at 90 PSI gravel impact, and no corrosion after 500 hours of both salt spray and water immersion testing, the strongest documented data in the category. Tack-free in 15 minutes; the 12-pack covers a full undercarriage in overlapping passes without running short mid-job.
The right buyer is a salt-belt or coastal daily-driver who wants the strongest documented performance in the category and can work a creeper with proper PPE. Skip it if the vehicle has active rust perforation; undercoating traps moisture over corroding metal and accelerates the problem, so a rust converter comes first. Also skip aerosol formats without cross-ventilation.
The SDS (Version 4.00, 2023) carries a DANGER signal word from reproductive toxicity and single-exposure organ toxicity classifications at the mixture level. SDS §8 specifies a supplied-air respirator, polymer laminate gloves, and a full face shield; exhaust ventilation is the engineering control. Prop 65 warning applies based on multiple listed ingredients in the US MSDS §15. VOC is 426 g/L. The cured film stays on the undercarriage; the mixture carries a chronic aquatic toxicity classification (H412).
SDS §2 (NZ GHS, Version 4.00, 2023) confirms the mixture-level classification includes H360 (Reproductive Toxicity Cat 1) and H370 (STOT-SE Cat 1, causes damage to the cardiovascular system from single exposure). These are severe GHS tiers and are the basis for the DANGER signal word on this product.
SDS §8 specifies a half facepiece or full facepiece supplied-air respirator. Overhead application beneath a vehicle in a semi-enclosed garage is a high-exposure scenario; SDS §8 engineering controls specify exhaust ventilation to prevent vapor build-up. At minimum, open doors and achieve cross-ventilation before spraying.
The 3M TDS documents 500-hour 5% salt spray resistance with no corrosion and excellent adhesion and abrasion ratings, comparable to top-tier category performance data. The owner review base is much smaller than Rust-Oleum's, so long-term multi-season community confirmation is thinner, though the 3M product sells strongly in the undercoating category.
The 16 oz aerosol cans are designed for overhead undercarriage application; standard any-angle aerosol use applies. The TDS recommends applying in multiple overlapping passes at the correct distance for full coverage of seams and frame rails.
This product is designed for bare or primed metal. Applying over active rust perforation or loose scale traps moisture beneath the film. Wire-brush or sand loose material first; if the surface has significant rust penetration, a rust converter or encapsulator is the correct first step before undercoating.
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