HAGATNA, Guam (AP) - In the U.S. territory of Guam, the Christmas season so far smells like frankincense, myrrh and methyl bromide.

The Pacific Daily News reports that Guam’s Customs and Quarantine’s BioSecurity Task Force is filling containers of imported Christmas trees with methyl bromide gas to kill potentially invasive species.

Officials say they have treated six containers of more than 2,500 imported trees, wreaths and garlands and expect to treat another seven containers in the coming weeks.

The Guam Invasive Species Council approved the fumigation policy in 2016 to keep unwanted pests from impacting Guam’s agriculture, natural resources or the homes of Christmas celebrants.

Each container is released after a customs inspection to ensure the treatment was successful.

The Environmental Protection Agency characterizes methyl bromide as a toxic fumigant and pesticide.