Does Contrac All-Weather Blox actually work?

Yes, and thoroughly — bromadiolone is highly palatable and potent enough to kill in a single feeding, with first deaths typically around 4-5 days later when secured correctly in an anchored, tamper-resistant station along real runways. It's genuinely a workhorse for rat and mouse cleanouts. The honest caveat is that its effectiveness depends entirely on licensed-level discipline: continuous fresh supply, anchored stations, and active carcass management, which is exactly why it's channeled to professional and agricultural sale rather than general retail.

Can I buy Contrac All-Weather Blox myself as a homeowner?

Generally, no — not in the container sizes and channels most homeowners can access. Second-generation anticoagulants like bromadiolone were restricted from general consumer retail sale following EPA action, and products like Contrac are now sold in bulk, professional and agricultural package sizes intended for licensed applicators. If you're seeing this product name in your research, it's most often because a pest control company is proposing or already using it, or because you're comparing options for a rat problem — either way, professional application is the realistic path to this specific active.

Why do I still have rats or mice after this bait was used?

The most common reasons are an interrupted bait supply, an unanchored or improperly placed station, unretrieved carcasses masking whether feeding actually happened, or — most often — an unsealed entry point letting new rodents replace the ones removed. Bromadiolone reduces the population that feeds on it; it does nothing to stop the next rodent from coming in through the same gap. Persistent activity despite correctly maintained bait is a signal to bring in a licensed technician for a fuller inspection and exclusion plan, not to add more bait.

How is bromadiolone different from bromethalin or brodifacoum?

All three are potent, professional-channel rodenticides, but they work differently. Bromadiolone and brodifacoum are both second-generation anticoagulants that disrupt blood clotting, with brodifacoum persisting longer in tissue and carrying the higher documented secondary-poisoning risk of the two. Bromethalin is a completely different class — an acute neurotoxicant with no antidote at all, versus the Vitamin K1 antidote available for anticoagulants like bromadiolone. A licensed technician chooses among them based on the infestation, the site's non-target risk, and how fast results are needed.

Is it safe to use around pets and wildlife?

Only when handled with real discipline. Bromadiolone carries genuine secondary-poisoning risk — a pet, hawk, owl, or other scavenger that eats a rodent that fed on the bait can be poisoned in turn, which is separate from the primary risk of an animal eating the bait directly. Responsible use means anchored, locked, tamper-resistant stations at all times and active searching for and removal of any rodent carcasses. For the full per-species pet-safety verdict, see our companion review at /is-pest-control-safe-for-pets/contrac-all-weather-blox-rodenticide-by-bell-laboratories.

How long does it take to see results?

First deaths typically occur around 4-5 days after rodents begin feeding, and a full cleanout — where sign visibly declines across droppings, gnawing, and sightings — usually takes 1-2 weeks with continuous, correctly maintained bait. That timeline assumes anchored stations stay stocked and undisturbed the whole time; any interruption in supply resets the clock on feeding rodents reaching a lethal dose, which is one more reason this product is best managed by someone monitoring it consistently, like a licensed technician.

Daniel Brady · NH-Licensed Pesticide Applicator · License #782664

How to Use Contrac All-Weather Blox Rodenticide by Bell Laboratories

Workhorse

Bromadiolone 0.005%

Contrac All-Weather Blox is bromadiolone, a second-generation anticoagulant rodenticide extruded into an all-weather paraffin block, and it's a genuinely effective single-feeding bait for rats and mice when secured inside an anchored, tamper-resistant station along active runways. Since EPA's restrictions on consumer sale of second-generation anticoagulants, this active is sold only through professional and agricultural channels in bulk container sizes — it isn't a typical hardware-store purchase, and it should never be used loose or outside a locked station. Done correctly, first deaths appear around 4-5 days after feeding begins. What it doesn't do is fix the entry point letting rodents in, and its real secondary-poisoning risk to pets, hawks, owls, and other predators that eat a poisoned rodent is exactly why this is a licensed-applicator tool. If you're researching this product because of rats or a recurring infestation, that's itself a signal to call a professional rather than to source and apply it yourself.

At a glance

Efficacy: Workhorse
Best job: Rat and mouse cleanouts and ongoing maintenance baiting in the hands of a licensed applicator using anchored, tamper-resistant stations
Format: Extruded paraffin bait block ('BLOX') with a center hole for securing on a rod inside an anchored, tamper-resistant station; labeled for Norway rats, roof rats, and house mice
Technique: Finicky technique

The honest verdict

Does this product actually work?

The verdict on this product

WorkhorseFinicky technique

Workhorse

A genuinely effective single-feeding rat and mouse bait — a professional-channel product that belongs in licensed hands, not a casual DIY cart.

Secured on the rod inside an anchored, tamper-resistant station along real runways, with fresh bait kept continuously available, bromadiolone is highly palatable and can kill in a single feeding, with first deaths around 4-5 days later — genuinely effective, professional-grade control. But it's channeled to professional and agricultural use in large container sizes specifically because of its secondary-poisoning risk to pets and wildlife that scavenge poisoned rodents, so this page explains the technique a licensed technician uses, not a shopping guide for a homeowner to apply it themselves.

Best for

Rat and mouse cleanouts and maintenance baiting programs run by a licensed applicator in anchored, tamper-resistant stations.

Skip it for

General consumer/DIY purchase — second-generation anticoagulants like bromadiolone are restricted from general retail sale, and any home use outside a locked station is unsafe and against the label.

Read the label first

What it is — and what it's really for

The label is the law. Here's the honest read on the format, the one job it does well, and the job people wrongly buy it for.

Format

Extruded paraffin bait block ('BLOX') with a center hole for securing on a rod inside an anchored, tamper-resistant station; labeled for Norway rats, roof rats, and house mice

Indoor / outdoor

both

Residual

The all-weather paraffin formulation resists moisture breakdown outdoors; effectiveness depends on keeping a fresh, uninterrupted supply in the station until feeding stops

Target pests

Norway rats, Roof rats, House mice

Best job

Rat and mouse cleanouts and ongoing maintenance baiting in the hands of a licensed applicator using anchored, tamper-resistant stations

Active ingredient

Bromadiolone (0.005%)

Not for (honest)

Casual consumer purchase — bromadiolone is a second-generation anticoagulant channeled to professional and agricultural sale in large container sizes since EPA's consumer restrictions, and it should never be used loose or outside a locked station

The technician's method

The technique walkthrough

Where DIY succeeds or fails is in the placement, patience, and the small pro moves the label never mentions. Follow the label; these are the technique details on top of it.

Finicky techniqueFirst deaths ~4-5 days after feeding begins; a full cleanout runs over 1-2 weeksTools:Gloves, Anchored tamper-resistant bait station, Securing rod, Flashlight for runway inspection

This is a professional-channel bait: the technique is correct, but so is the honest framing that it's built for licensed application, not a beginner's first rodenticide purchase.

Confirm rodent travel routes
Identify where rodents travel — along walls, near gnawed openings, corners, and concealed places — before placing any station.
Pro move
Look for grease-rubbed runways along foundation lines outdoors, not just indoor sign.
Secure BLOX in an anchored, tamper-resistant station
Thread the block onto the interior rod of a locked, tamper-resistant station and anchor the station itself so it can't be dragged off or tipped.
Common mistake
Using bait loose or in an unanchored box — illegal under the label and a serious non-target hazard.
Caution
Broadcasting or burrow-baiting this product is prohibited by label.
Space stations along runways
Place multiple anchored stations at intervals along the runways identified, indoors and out per label guidance.
Maintain an uninterrupted fresh supply
Check regularly and keep bait fresh until feeding stops — a station that runs empty stops contributing and can create bait shyness.
Pro move
Alternate palatable bait formats in stubborn accounts to counter shyness.
Retrieve carcasses where possible
Search for and remove dead rodents near stations to reduce the chance of a pet or scavenger eating a poisoned carcass.
Caution
Secondary poisoning is a real risk with this active — treat any dead rodent as a hazard.
Pair with sanitation and exclusion
Remove competing food sources and seal entry points — bait reduces the population present, it doesn't stop the next rodent from getting in.

Habits that decide it

Do & don't

Use only in anchored, tamper-resistant stations.
Keep bait fresh and continuously available.
Document and monitor placements.
Retrieve rodent carcasses when found.
Pair baiting with sanitation and exclusion.

Don't

Don't broadcast or burrow-bait.
Don't use loose bait or an unanchored station.
Don't place near food-contact surfaces.
Don't treat this as a casual consumer purchase.
Don't leave a dead rodent where pets or wildlife can scavenge it.

The honesty moat

Where it works vs. where it fails

No product fixes everything. This is the honest boundary — the situations it genuinely handles, and the ones it simply won't.

Where it works

A licensed applicator is running a rat or mouse cleanout with anchored, tamper-resistant stations
Fresh bait supply is monitored and maintained continuously
Sanitation and exclusion are addressed alongside baiting
The setting allows carcass search-and-removal to limit secondary exposure

Where it fails

Used as a casual, unsupervised DIY purchase — it's restricted to professional/agricultural channels for a reason
Placed loose or in an unanchored station
There's no plan for carcass retrieval where pets or predators could scavenge
Entry points stay unsealed, letting new rodents keep replacing the ones removed

Don't throw money away

Mistakes that waste the product

Using it outside a locked, anchored station

Loose or unanchored placement is unsafe, illegal under the label, and risks non-target poisoning.

Fix

Always secure BLOX inside a locked, tamper-resistant, anchored station.

Letting the bait supply run out

An interrupted supply under-doses feeding rodents and can build bait shyness.

Fix

Check regularly and keep fresh bait available until feeding stops.

Leaving carcasses in place

A pet or scavenging predator can be secondarily poisoned by eating a rodent that fed on the bait.

Fix

Search for and remove dead rodents near bait stations.

Skipping exclusion

Without sealing entry points, new rodents keep replacing the ones the bait removes.

Fix

Pair baiting with a real exclusion program.

Calibrated expectations

What to expect — and when

Bromadiolone can kill in a single feeding, but a full cleanout still runs over days to weeks as remaining rodents encounter the bait.

First few days
Rodents locate and begin feeding on properly placed, anchored stations.
About days 4-5
First deaths typically occur, per the documented feeding-to-mortality window for this active.
1-2 weeks
Sign declines as the population present is reduced, assuming continuous bait supply and exclusion work.

When results plateau

Results plateau without exclusion or carcass management — new rodents replace the ones removed, and the secondary-poisoning risk keeps compounding the longer dead rodents go unretrieved.

Know the ceiling

When to stop DIY & call a pro

This is a professional-channel product from the start — these are the signals it's time to bring in a licensed technician rather than attempt to source and apply it yourself:

You're seeing rats, not just mice, anywhere in or around the structure
Rat-scale infestations need denser, licensed placement and inspection depth a homeowner can't match.
Activity continues despite what looks like correctly maintained bait
Persistent activity with a potent second-generation active usually points to an entry-point or scale problem beyond baiting alone.
You can't guarantee every station stays anchored and inaccessible to pets, kids, and wildlife
The secondary-poisoning and access risks with this active are serious enough that inconsistent control is a real hazard.
You find or suspect a dead rodent you can't safely retrieve
Unretrieved carcasses are the main pathway for secondary poisoning of pets and predators.

Contrac All-Weather Blox is exactly the kind of product Anchor's licensed NH technicians are trained and equipped to apply — professional-grade bait in anchored, tamper-resistant stations, with the inspection, monitoring, and exclusion work that makes it safe and effective. Free inspection, same-day service across southern and central New Hampshire.

Dealing with rats, not just a mouse or two?

Get a Free inspection (603) 785-0118

Before you treat

Is it safe for pets & kids?

The short version lives here; the full per-species verdict lives on this product's pet-safety page.

Bromadiolone is a second-generation anticoagulant with meaningful secondary-poisoning risk — a pet or predator that eats a poisoned rodent can be harmed, not just an animal that eats the bait directly. Vitamin K1 is the antidote, administered by a vet or doctor, never at home. This product must stay inside a locked, anchored, tamper-resistant station at all times.

Re-entry: Keep bait stations locked, anchored, and completely out of reach of children, pets, and non-target wildlife — this isn't a product to leave loose under any circumstances.

If there's an exposure, call

ASPCA Animal Poison Control: (888) 426-4435 Pet Poison Helpline: (855) 764-7661 Northern New England Poison Center: (1-800) 222-1222

See the full per-species pet-safety verdict for this product

New Hampshire context

Why this product usually means calling a professional in New Hampshire

Because bromadiolone is restricted to professional and agricultural channels, most southern and central NH homeowners encounter this product name while researching a rat problem, not while shopping a store shelf. Anchor's licensed technicians carry and correctly apply this and other professional-grade rodenticides as part of a full cleanout — inspection, station placement, monitoring, and exclusion — across Manchester, Nashua, Concord, and the surrounding towns.

Service area

Southern New Hampshire

Anchor Pest Services · NH license #782664 · NEPMA member · family-owned since 2017.

Common questions

Frequently asked

Sources & further reading(4)

[1]
EPA Registered Product Label — Contrac All-Weather Blox (Reg. No. 12455-79)
Verified active (bromadiolone 0.005%), tamper-resistant station requirement, target pests
epa_labelverified 2026-07-14
[2]
Bell Laboratories — Contrac All-Weather Blox product page
Format, all-weather paraffin block facts (facts only, not the efficacy verdict)
manufacturerverified 2026-07-14
[3]
EPA — Restrictions on Rodenticide Products
Second-generation anticoagulants restricted from general consumer sale; professional/agricultural channel context
govverified 2026-07-14
[4]
NPIC — Rodenticides General Fact Sheet
Second-generation anticoagulant mechanism, secondary-poisoning risk, Vitamin K1 antidote
npicverified 2026-07-14

Written & reviewed by

Verified

Daniel Brady

NH-Licensed Pesticide Applicator · License #782664 (NHDAMF, RSA 430)

Daniel Brady is the New Hampshire–licensed applicator behind Anchor Pest Services, a family-owned pest control company serving the Manchester area since 2017.

Verify license

Last updated July 2026

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Professional Pest Control

A Professional-Channel Product, Applied Professionally

Contrac All-Weather Blox is potent, effective, and restricted for good reason. Anchor Pest Services applies it (and other professional rodenticides) with the anchored-station discipline, carcass management, and exclusion work that keeps it safe and effective across southern and central New Hampshire. Family-owned since 2017, NH license #782664.

Get a Free inspection (603) 785-0118

Licensed application of professional-grade rodenticides
NH-licensed applicators (#782664)
Free inspection — same-day service across southern NH

NH License #782664 · No obligation · We answer in person

Keep Exploring

How to Use Contrac All-Weather Blox Rodenticide by Bell Laboratories

Does this product actually work?

What it is — and what it's really for

The technique walkthrough

Confirm rodent travel routes

Secure BLOX in an anchored, tamper-resistant station

Space stations along runways

Maintain an uninterrupted fresh supply

Retrieve carcasses where possible

Pair with sanitation and exclusion