Formaldehyde solution, less than 10 percent

Carry On Bags: Yes (Less than or equal to 3.4oz/100 ml allowed)
Checked Bags: Yes (Special Instructions)

Formaldehyde solutions of less than 10% are not restricted as hazardous materials. Leak-proof packaging with absorbent material is still strongly encouraged.  For formaldehyde solutions containing more than 10% formaldehyde, see separate entry for "Biological specimens in preservative solutions."

Tip: Full-strength "Formalin" is typically 35%-40% formaldehyde by volume. So a solution that is less than 25% Formalin would be less than 10% formaldehyde and not restricted.

 The final decision rests with the TSA officer on whether an item is allowed through the checkpoint.