X, Y, Z
Z List The Occupational Safety and Health Administration (OSHA) Toxic and Hazardous Substances (Tables Z.1, Z.2, and Z.3) of air contaminants, found in 29 CFR 1910.1000. These tables record permissible exposure limits (PELs), time-weighted averages (TWAs), and ceiling concentrations for the materials listed. Any material found in these tables is considered to be hazardous. The tables can be viewed on OSHA’s Web site:
Table Z.1: http://www.osha.gov/pls/oshaweb/ owadisp.show_document?p_table=standards&p_id=9992
Table Z.2: http://www.osha.gov/pls/oshaweb/ owadisp.show_document?p_table=STANDARDS&p_id=9993
Table Z.3: http://www.osha.gov/pls/oshaweb/ owadisp.show_document?p_table=STANDARDS&p_id=9994
Zero Energy The state of a piece of equipment when all sources of energy (i.e., electrical, mechanical, hydraulic, etc.) is isolated from the particular piece of equipment or is effectively blocked and all sources of stored energy are depleted.