Since 1965

Instructional Videos / Demonstrations:

https://www.youtube.com/watch?v=MkY3dH4MGq0

https://www.youtube.com/watch?v=lw-ylJ6bW7E

OSHA Regulations: 

https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9825