Black Flag
Black Flag Propane Insect Fogger
Fogger · EPA-registered pesticide
Pros
- Knocks bugs down fast to clear an area for an event (40–70%)
- Treats a large area (about 5000 sq ft)
- EPA-registered product
- Active ingredient concentration disclosed
Cons
- Kills on contact but wears off within minutes to a few hours, with little residual — not lasting protection
- Non-selective: it also kills bees and other beneficial insects
- Highly toxic to fish and aquatic life — keep well away from water
The full review
Propane thermal fogger from Black Flag that heats a d-phenothrin fogging insecticide into a fog to knock down and kill mosquitoes, biting flies, and gnats across a yard. The label points to treating an average 5,000 square foot yard in about ten minutes. Killing is on contact and fast, but there is little meaningful residual outdoors, so a treated yard stays clear for only a few hours before insects return from surrounding areas. People and pets can re-enter once the visible fog clears, usually within a few minutes. Because the fog is non-selective it also kills bees and other beneficial insects it reaches, so it works as a short-term event tool rather than sustained protection.
Scorecard
Expand any pillar to see exactly why it scored what it did.
Effectiveness45%38A fogger knocks down and kills the mosquitoes present when you use it, cutting bites by roughly 40–70% for a short window, over about 5000 sq ft. It works by killing on contact, not repelling, and has little residual, so the effect fades within minutes to a few hours as new mosquitoes move back in. Scored on that reduction and treated area, then tempered because it clears a space for an event rather than providing lasting protection (lower confidence).
A fogger knocks down and kills the mosquitoes present when you use it, cutting bites by roughly 40–70% for a short window, over about 5000 sq ft. It works by killing on contact, not repelling, and has little residual, so the effect fades within minutes to a few hours as new mosquitoes move back in. Scored on that reduction and treated area, then tempered because it clears a space for an event rather than providing lasting protection (lower confidence).
Evidence & honest claims25%13No published studies in our library directly support this product's active ingredients at their concentrations (base 20). Of 4 marketing claims audited: 0 strong, 3 moderate, 1 weak, 0 unsupported (-7).
No published studies in our library directly support this product's active ingredients at their concentrations (base 20). Of 4 marketing claims audited: 0 strong, 3 moderate, 1 weak, 0 unsupported (-7).
Safety15%60This is an area treatment, not applied to skin, so dermal risk does not apply. Scored on moderate inhalation risk from the fog (−18); high toxicity to fish and aquatic life (−22). It kills insects non-selectively, so it also harms bees and other pollinators. Fog outdoors only, away from people and flowering plants, keep cats away. Keep it well away from ponds, aquariums, and water features.
This is an area treatment, not applied to skin, so dermal risk does not apply. Scored on moderate inhalation risk from the fog (−18); high toxicity to fish and aquatic life (−22). It kills insects non-selectively, so it also harms bees and other pollinators. Fog outdoors only, away from people and flowering plants, keep cats away. Keep it well away from ponds, aquariums, and water features.
Transparency15%75This product publishes an ingredient list (+20); discloses 100% of active concentrations (+40); discloses 100% of all ingredient concentrations (+15); inert ingredients are not fully accounted for (0).
This product publishes an ingredient list (+20); discloses 100% of active concentrations (+40); discloses 100% of all ingredient concentrations (+15); inert ingredients are not fully accounted for (0).
Every pillar is scored from published rules. Read how we score.
Coverage & effectiveness
This is a fogger: it kills the mosquitoes present when you use it across a treated area, then wears off within minutes to a few hours as new mosquitoes return. It clears a space for an event rather than providing lasting protection.
Mosquitoes
EstimatedLow- Treated area
- ~5000 sq ft
- Fewer bites
- 40–70%
Black Flag's d-phenothrin fog kills mosquitoes, gnats, and biting flies on contact and knocks down the population present in a yard, but there is little meaningful residual once the fog clears. The yard stays comparatively clear for a few hours before insects return from surrounding areas, so the effect is a temporary knockdown, not lasting protection. The band shown is an estimate for that brief window and varies with wind and coverage. As a non-selective insecticide the fog also kills bees and other beneficial insects, so it should be reserved for occasional event use.
Ingredient disclosure
This product publishes an ingredient list (+20); discloses 100% of active concentrations (+40); discloses 100% of all ingredient concentrations (+15); inert ingredients are not fully accounted for (0).
Only active ingredients are disclosed. The full ingredient list (inerts/carriers) is not published, so this may not be the complete formula.
- PhenothrinActive
Active insecticide · 0.15%
Claims audit
What the marketing says, versus what the evidence supports.
“High knockdown and kill on contact for flying and crawling insects”
EfficacyModerateFast contact kill is accurate for insects the fog reaches during treatment.
“Treats an average 5,000 sq ft yard in about 10 minutes”
EfficacyModerateA fair measure of area coverage per fogging. The knockdown across that area is temporary.
“Provides quick killing action and residual control”
DurationWeakThe quick kill is real, but meaningful outdoor residual is limited. Insects return within a few hours, so lasting residual control is overstated.
“Nearly odorless, leaves an odor-free backyard”
OtherModerateBroadly accurate for the current formula. It is not a measure of how long protection lasts.
Safe around dogs & cats?
Worst case from this product’s active ingredients. Do not apply this or any human repellent to your pet.
Mainly from Phenothrin.
Not veterinary advice. Full guide to repellents around pets →