The Dangers of Bulging LiPo Batteries: Fire Risks and Safety Precautions (2025 Guide)

If your lithium‑polymer (LiPo) battery looks puffed or feels swollen, stop using it immediately. This guide shows you exactly how to make the situation safe, how to package and dispose of the battery in the U.S., and how to prevent it from happening again.

• Difficulty: Moderate (safety-critical)
• Time to stabilize and package: 30–90 minutes (not counting travel to drop-off)
• You’ll need: Nonflammable surface (ceramic/concrete/metal tray), metal container with a loose-fitting lid, dry sand or clay-based cat litter, non-conductive tape, nitrile gloves, safety glasses, a charged ABC fire extinguisher

Quick Action Box: First 5 Minutes

Do this now:

1. Power down and disconnect the device. Do not charge or use the battery.
2. Move the battery to a nonflammable surface (ceramic tile, concrete floor, or metal tray) away from anything that can burn (at least 10 feet).
3. Ventilate the area. If you have gloves and safety glasses, put them on.
4. Observe for heat, smoke, odor, or hissing. If it gets hot, smokes, or you see flames, evacuate and call 911 immediately.
5. If stable (cool, no smoke), prepare containment: place it in a metal container with a little dry sand or clay-based cat litter at the bottom. Do not seal airtight; rest a lid loosely on top.

Don’t do this (common, dangerous mistakes):

• Do not puncture, squeeze, or “vent” the battery.
• Do not put it in the trash or curbside recycling.
• Do not “saltwater discharge” or try to fully discharge a swollen pack at home.
• Do not charge it “to test it.”

Who to call next (U.S.):

• Your municipal Household Hazardous Waste (HHW) program.
• A participating battery retailer or stewardship program (see Call2Recycle locator).
• For active smoke/odor/leak in an occupied building, follow local guidance—FDNY advises moving away from combustibles if safe and calling 911.

According to the U.S. Consumer Product Safety Commission (CPSC) in 2025, “Do not throw this defective lithium-ion battery or device in the trash, in the general recycling stream (e.g., street-level or curbside recycling bins), or in used battery recycling boxes found at various retail and home improvement stores. Defective lithium-ion batteries must be disposed of differently than other batteries, because they present a greater risk of fire,” as stated on the CPSC NEWDERY power bank warning (2025).

How to Recognize a Bulging LiPo

• Visible swelling or a pillow-like look, especially on pouch cells
• Case splitting, lifting screens (in devices), or difficulty closing battery doors
• Sweet/solvent odor, hissing, or unusual warmth even when not in use
• Rapid self‑discharge or charger errors; for multi‑cell packs, large cell‑to‑cell voltage imbalance (advanced users only)

If any of these signs appear, treat the battery as damaged/defective and follow the Quick Action steps.

Why Swelling Is Dangerous (Plain-English)

Swelling means gases are building up inside the pouch because the battery’s internal chemistry is breaking down—often from overcharge, deep discharge, heat, age, or physical damage. The gas raises pressure and can force flammable vapors out if the pouch ruptures. Heat or sparks can ignite those vapors, leading to rapid fire and the potential for thermal runaway.

The U.S. Environmental Protection Agency emphasizes that lithium-ion batteries pose a fire danger when mishandled or tossed into household trash and should go to specialized recyclers or hazardous waste facilities. See the EPA’s 2024–2025 guidance on the importance of sending used lithium-ion batteries to recyclers or HHW programs and their page noting that discarded lithium-ion batteries are often considered ignitable/reactive hazardous waste in the EPA lithium-ion battery recycling overview.

Immediate Actions (Step-by-Step)

1. Make space and reduce ignition sources
   • Clear a 10‑foot radius of combustibles (paper, fabrics, solvents). Open windows if possible.
2. Isolate on a nonflammable surface
   • Use a ceramic tile, concrete floor, or a metal tray. Do not set it on wood or carpet.
3. PPE and positioning
   • Wear nitrile gloves and safety glasses if available. Keep your face out of the line of venting. Keep pets and children away.
4. Prepare containment
   • Place a thin layer (about 1 inch) of dry sand or clay-based cat litter in a clean metal container (steel pot, metal ammo can with the latch open, or paint can). Do not use a sealed, airtight container.
5. Transfer the battery
   • Gently place the battery on top of the sand. Rest a metal lid loosely on the container—enough to deflect any flare‑ups but not sealed, so gases can vent.
6. Monitor for 30–60 minutes
   • Feel for warmth with the back of your hand near (not on) the container. Watch for smoke, odor, or swelling progression. If heating or smoke begins, evacuate and call 911.
7. Label and set aside
   • Mark the container “Damaged Li-ion Battery – Do Not Use.” Store on a nonflammable surface, away from sun or heat, until you can take it to HHW or a qualified recycler.

Checkpoint: It’s reasonably safe to prepare for transport when the battery is cool to the touch, shows no increase in bulging over 30–60 minutes, and there’s no odor or hissing.

Temporary Storage and Transport Prep (U.S.)

• Tape or bag the terminals
  • To prevent short circuits, tape exposed terminals with non-conductive tape, or place the battery in an individual clear plastic bag. This aligns with the consumer prep guidance to “bag or tape your batteries” from the Call2Recycle battery recycling page.
• Use sturdy, nonflammable containment
  • Keep it in the metal container with sand during transport. Keep the lid loose. Do not pack with metal tools or other batteries.
• Keep it cool
  • Transport promptly. Avoid leaving the battery in a hot car. Place the container on the floor of the vehicle, secured from tipping.
• Call ahead (DDR handling)
  • Swollen or damaged batteries are considered “damaged, defective, or recalled” (DDR) and may require special handling. Regular retail drop-boxes often do not accept DDR batteries; confirm instructions before you go via the Call2Recycle DDR handling notes.

The CPSC advises contacting your municipal HHW collection center for disposal and to call ahead to confirm they accept defective lithium-ion batteries, as noted in the CPSC 2025 NEWDERY warning.

How to Dispose or Recycle in the U.S. (2025)

• Never use household trash or curbside recycling
  • The EPA and CPSC both warn against this due to fire risks in waste streams. See the EPA explainer on keeping Li-ion batteries out of household trash and curbside recycling and the CPSC’s 2025 warning language.
• Options that typically accept lithium-ion batteries
  • Municipal HHW collection events or facilities (call first for DDR instructions)
  • Participating retailers with battery take-back programs (DDR exceptions apply)
  • Stewardship programs; use the Call2Recycle locator and ask for DDR guidance
• What to say at drop-off
  • “This is a damaged/swollen lithium-ion battery (LiPo). It’s cool and contained in a metal container with sand. How would you like me to transfer it?”
• Documentation (for workplaces/EHS)
  • Keep a simple log: date discovered, actions taken, condition (cool, no smoke), where delivered, and staff instructions received. This helps with compliance and training.

Prevention: Charging, Storage, and Use

Charging

• Use a charger designed for LiPo with balance leads. Set max voltage to 4.2 V per cell and limit current to ≤1C unless your battery manufacturer specifies otherwise.
• Charge on a nonflammable surface, away from combustible materials. Never leave charging batteries unattended.
• Consider a LiPo-safe charging bag or a metal tray as secondary containment.

Storage

• Store at about 30–60% state of charge (often called “storage charge”).
• Keep in a cool (not freezing), dry place. Avoid direct sunlight and hot vehicles.
• Do not compress, bend, or stack heavy items on packs. Separate packs so they cannot short against each other.
• Inspect monthly for swelling, odor, or damage. Remove any suspect pack from service immediately.

Use

• Avoid deep discharge (try not to go below ~20% state of charge).
• Keep packs within their rated temperature range; avoid mounting near motors or heat sources without airflow.
• Protect from puncture and vibration. Use proper mounts and padding.
• For multi‑cell packs, keep cells balanced; retire packs that repeatedly show imbalance or unusual warmth.

If a LiPo Starts Smoking or Catches Fire

• Evacuate and call 911
  • The NYC Fire Department instructs residents to call 911 for any lithium-ion battery emergencies and to stop using and move the battery away from anything flammable if it is emitting odor, changing shape/color, or leaking, per the FDNY lithium-ion safety page.
• Extinguish only if safe and incipient
  • If a small fire involves nearby materials (not the battery core itself) and you can do so safely, use an ABC extinguisher to knock down those flames and prevent spread. Do not take risks.
• Cooling and re‑ignition risk
  • Research from UL’s Fire Safety Research Institute shows water is effective for cooling exposures and that re‑ignition can occur even after visible flames are out; monitoring and continued cooling may be needed, as seen in the FSRI water suppression research update. FSRI has also cautioned that covering battery fires with blankets can trap flammable gases and present an explosion risk, noted in their FSRI fire blanket hazard news.
• After the incident
  • Do not handle debris until fully cooled and cleared by responders. Expect lingering odors and off‑gassing; ventilate thoroughly. Treat the remains as hazardous and follow local instructions.

FAQs

Q: Can I discharge a swollen LiPo to make it safer? A: Do not attempt to discharge a damaged/swollen LiPo at home. Damaged, defective, or recalled (DDR) batteries require special handling, and consumer programs often prohibit DDR batteries from regular drop‑boxes. Follow HHW or stewardship instructions, consistent with Call2Recycle’s DDR handling notes.

Q: Is a LiPo-safe bag enough protection by itself? A: Treat LiPo bags as secondary containment. Use a nonflammable surface and, for damaged packs, a metal container with a loose lid and an absorbent buffer like sand or clay‑based cat litter.

Q: Can a bulging LiPo explode? A: Swollen packs can vent flammable gases that may ignite violently if exposed to heat or sparks. The safest assumption is that fire is possible—handle as outlined here and keep distance from combustibles. The EPA underscores waste‑stream fire dangers for mishandled lithium-ion batteries in its battery recycling guidance.

Q: How long should I monitor a swollen pack before transport? A: Monitor for at least 30–60 minutes on a nonflammable surface. Transport only when cool and stable, in a metal container with sand, and after calling ahead for DDR instructions.

Q: What about built‑in batteries (phones, laptops, e‑bikes)? A: If the device is swelling, stop using it and, if safe, move it away from combustibles. Do not attempt to remove glued‑in packs if you’re not trained—contact the device maker or an authorized service provider, or take the entire device to HHW after calling ahead. If there is smoke/odor/heat, evacuate and call 911 as advised by the FDNY.

Quick-Reference Checklist (Printable)

• Stop using/charging immediately
• Move to ceramic/concrete/metal surface in a clear area
• PPE on; ventilate space
• Place in metal container with 1 inch of sand/clay litter; lid loose
• Monitor 30–60 minutes; label container
• Tape or bag terminals; secure for transport; keep cool
• Call HHW or stewardship program for DDR instructions; drive directly to drop‑off (no curbside)

Why we advise against DIY “saltwater discharge” and puncturing

Consumer safety agencies direct damaged batteries to specialized programs and warn against putting them in trash or regular recycling streams; this implies DIY destruction methods are unsafe and noncompliant. For example, the CPSC’s 2025 warning language and the DDR restrictions from Call2Recycle’s program show that swollen/damaged batteries require special handling and should not enter standard channels. See the CPSC 2025 warning and Call2Recycle consumer prep with DDR note.

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Important: Follow your local regulations and the battery/device manufacturer’s instructions. When in doubt, choose the safest option: isolate, evacuate if heating or smoking, and contact professionals.