CarCareTruth Score
Decent.
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The 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 aspiration toxicity — thin, oily liquids can slip into the lungs if swallowed, causing chemical pneumonia.
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.
This product ranks #4 of 6 in Oil Additive.Three above it ↓
Last reviewed June 12, 2026
TL;DR Petroleum-based cleaning concentrate · the active chemistry is a hydrocarbon-based detergent blend with no ZDDP or tribological anti-wear compound. DANGER signal word is driven by an aspiration hazard at concentrate strength; do not induce vomiting if ingested · seek medical attention.
Sea Foam Motor Treatment uses a proprietary hydrocarbon-cleaning blend to dissolve sludge, varnish, and deposits in the crankcase and fuel system. The mechanism is solvent-detergent cleaning, not anti-wear tribology. Community evidence is substantial: highly rated by a very large owner base with consistent reports of smoother idle after crankcase pre-drain treatment. No ZDDP or phosphorus compounds · no catalytic converter concerns. Compatible with gasoline and diesel engines, conventional and synthetic oil.
Best for owners of older or high-mileage engines who suspect sludge buildup and want a cleaning pass before an oil change · and for fuel stabilization in stored vehicles or small engines. Skip if you need a genuine anti-wear additive: Sea Foam is a cleaner, not a tribological supplement.
DANGER signal word from an aspiration hazard · do not induce vomiting if ingested, seek medical attention. SDS §2 classifies skin irritation (H315), eye irritation (H319), and respiratory irritation (H335) at mixture level. No Prop 65 chemicals per SDS §15. Petroleum-derived drain-destined concentrate. Used oil goes to a collection facility · not the drain.
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