TPO Photoinitiator Reclassification: What Formulators Need to Know

Regulatory changes are not always on our radar, so I thought I’d share a very brief update on the key “Need to Know” datapoints related to TPO. 

TPO has been reclassified from Reproductive Toxicity Category 2 (Repr. 2) to Reproductive Toxicity Category 1B (Repr. 1B) across major regions (ex. Europe, USA, China…) indicating increased concern over reproductive toxicity.  This has triggered new GHS hazard statements and labeling requirements.

Highlights of the Old Classification:

• GHS Category: Repr. 2 (H361f)

• Signal Word: Warning

• Label Symbol: GHS08

• Transport Classification: Not regulated

New Classification Changes

• GHS Category: Repr. 1B (H360Fd), Skin Sens. 1B (H317), Aquatic Chronic 2 (H411)

• Signal Word: Danger

• Label Symbols: GHS07, GHS08, GHS09

• Transport Classification: UN3077; Class III (ADR, IATA, IMDG)

What This Means for Formulators

If you are using TPO in your inkjet inks, OPVs, adhesives, or coatings, the reclassification will require you to:

• Update SDS and relevant hazard communications

• Reevaluate safe handling, PPE, and waste protocols

• Assess fit for use concerns in end applications with downstream customers.

• Potentially reformulate products for markets sensitive to reproductive toxicity or aquatic hazard labeling

OSHA Compliance Timeline

Under OSHA’s updated Hazard Communication Standard, aligned with GHS, companies must update their hazard documentation in two phases:

Material Type	SDS & Label Deadline
TPO	January 19, 2026
Formulations	July 19, 2027

Compliance ensures you can continue using TPO in your formulations with updated documentation reflecting the new hazard classification.

Need Help?

Summit Analytical can assist companies who need to revise their formulations to comply with the new classification. Whether you're looking for a TPO-free UV ink, alternative Type I/II photoinitiators, or want to evaluate a complete formulation redesign strategy, we can help you optimize performance while staying ahead of regulations.