FAQs

  1. Why does Spokane County have a Noxious Weed Control Board and what does it do?
  2. How is Weed Control Enforced?
  3. How is the Program Funded?
View All

Herbicides and Other Chemicals


All chemicals are assigned Lethal Dose (LD 50) numerical values through certain testing procedures. What LD 50 means is the dose or amount of a pesticide which can kill 50% of the test animals when eaten or absorbed through the skin. LD50 is expressed in milligrams of chemical per kilogram of body weight of the test animal (mg/kg). The lower the LD50 the more acutely toxic the chemical.

Chemical Name Lethal Dose (LD 50) Half Life
Gasoline 19 N/A
Caffeine 190 N/A
2,4-D 300 - 1,000 7 to 28 days
Aspirin 1240 N/A
Banvel 1700 5 months
Table Salt 3320 N/A
Telar / Glean 5545 3 months
Roundup 5600 7.5 days
Tordon 8200 5 months / pint