Published: Jan. 9, 2018

Students walk by Farrand Field, where many of the surrounding oak trees are infected with Allokermes scaleLast month, we notified you that, during winter break, a contractor working for Facilities Management Outdoor Services was going to conduct a broadcast spray application of a dormant food-grade soybean oil insecticide to as many as 25 oak trees on Main Campus.

These trees are infested with Allokermes scale, which affects the trees’ health and makes them susceptible to other secondary diseases. This work started on Jan. 5 and was completed on Jan. 8.

Unfortunately, the contractor used a different product that contains a chemical called naphthalene, which is a possible human carcinogen. As soon as Facilities Management officials identified the mix-up, they halted the project, but approximately 90 percent of the affected trees had been treated. According to the Environmental Protection Agency, common exposure routes for naphthalene include ingestion, inhalation and skin exposure while the chemical is being applied.

The trees will not be negatively impacted. Naphthalene is an industry option for the treatment of Allokermes scale. However, it is one the campus did not prefer. The project was completed using the originally planned food-grade soybean oil insecticide.

The affected trees were marked with yellow application notice flags that will indicate where the application was made. Federal law requires these flags remain in place for 24 hours after an application has been made. In the interest of keeping the campus community informed, CU Boulder staff will leave these flags in place until Jan. 16.

With any questions or concerns, contact Don Inglis at 303-735-6311 or Rob Lenahan at 303-735-3627 in Facilities Management.