Read the label of an herbicide before you use it, and follow the instructions to the letter. Don't spray on a hot or windy day, and don't let the spray touch desirable plantsùit'll kill them.
Safety-related resources on the Web:
Index of Occupational Safety and Health Resources (http://turva.me.tut.fi/~oshweb/)
National Safety Council (http://www.national-safety-council.ie/)
National Institute for Occupational Safety and Health (http://www.cdc.gov/niosh/homepage.html)
Other safety Web sites
To make digging easier, make sure the lawn is moist before you start.
spade
steel rake
wheelbarrow
spray tank
sod cutter
Tool and hardware-related resources on the Web