Safety and fumes

FGF (Fused Granular Fabrication) pellet printing with the G1 melts plastic at high temperatures, which releases volatile compounds and ultrafine particles. This note covers what is safe, what requires ventilation, and how to recognize contaminated or wrong material.

Baseline: PLA and PETG

PLA and PETG are among the safest materials for 3D printing:

• PLA emits lactic acid derivatives — low toxicity, mild smell (slightly sweet)
• PETG emits small amounts of ethylene glycol and acetaldehyde — low risk with normal ventilation

Minimum recommended: print in a room with a window open or a fan providing air exchange.

Materials that require active ventilation

Material	Compound	Action
ABS / ASA	Styrene (known irritant)	Dedicated ventilation or air filtration mandatory
Nylon (PA)	Caprolactam fumes	Ventilate well; avoid extended exposure
PETG V0 (flame retardant)	FR additives, brominated compounds	Ventilate well, do not exceed recommended temperature
Carbon fiber filled	Fine carbon particulates	Ventilation + consider N95 mask when handling powder
Recycled materials (unknown source)	Unknown contaminants	Ventilate; if unusual smell appears, stop and air the room

Recognizing contaminated or wrong material

If the material smells strongly unusual (chemical, ammonia-like, acrid, rubber-like), it may be:

• Contaminated with a different polymer (seen with some recycled PLA batches)
• The wrong material (mislabeled by supplier)
• Thermally degraded (overheated or left in the barrel too long)

Action: stop the print, ventilate the room, check with the supplier. Do not continue printing a material that smells wrong.

Note

From a customer case (Poland): received rPLA that smelled like a different plastic — the batch was likely contaminated. A chemist confirmed it was not pure PLA.

Burning smell / smoke

If you see smoke or smell burning:

1. Stop the print immediately
2. Check for material degraded in the barrel — overheating or a clog can cause degradation
3. Ventilate the space
4. Check the temperature setpoints — an overheated zone can degrade material

Never ignore smoke or an acrid burning smell — it means plastic is degrading, not just melting.

Carbon monoxide risk

Pellet printing does not normally produce CO in dangerous quantities with standard thermoplastics. CO is only a risk with materials containing organic pigments or additives burned at much higher temperatures than the G1 operates.

UPS and mains safety

The G1 draws up to 2000W. Use appropriate mains wiring:

• Dedicated 16A circuit recommended
• Do not use extension cords rated for less than the machine’s draw
• A UPS can protect against power dips — see Raspberry Pi and SD card

Related notes

• PETG foaming and moisture — bubbles/popping sounds vs actual chemical hazard
• PETG flame retardant V0 — FR materials need extra ventilation
• PP and specialty materials — ABS/ASA ventilation requirements
• Multi-Heating Zones — avoid overheating zones that degrade material