Gardaí are concerned about the danger posed by insulation bales in the run-up to Halloween.
Some 20 bales were robbed in Co Louth at some point over the last four days.
The items were taken from a building site on Strand Road in Termonfeckin.
Gardaí warned that the bales will emit toxic fumes and smoke if set alight.
This has the potential to harm the health of anyone who comes into contact with them without appropriate breathing apparatus, they said.
Anyone with information has been asked to contact Drogheda garda station on 041 987 4200 or the garda confidential line on 1800 666 111.
Image: Garda Press Office