UC San Diego and the UC Office of the President have succeeded in their attempts to convince the state regulators to drop a prerequisite on the use of sulfur hexafluoride (SF6) gas, a greenhouse gas, in the safety tests of newly installed laboratory fume hoods.
A tracer gas test needed by California Occupational Safety and Health Administration (Cal-OSHA) reflects the testing standards formulated by American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) in 1995 that suggests the use of sulfur hexafluoride or similar gas for the tests. Now Cal-OSHA has approved the change and made it applicable exclusively for 10 UC campuses in the state and may be applied all over California to reduce energy usage and greenhouse gas emissions.
UC San Diego will henceforth utilize nitrous oxide gas, which is considered to be a less risky alternative when compared to SF6. The SF6 emissions were found to be 22,800 times more powerful than CO2 in warming the lower atmosphere of the Earth. Every 20 minute test conducted over a single fume hood utilizing SF6 discharges around 10 metric tons of CO2.
The nitrous oxide suggested as an alternative by UC San Diego is also a greenhouse gas that has around 1% of the global warming effect of SF6. While the nitrous oxide gets eroded and looses its potency in around 120 years, the more potent SF6, though non-toxic to human beings, stays in the atmosphere for thousands of years.
The application for using nitrous oxide was approved by the Occupational Safety and Health Standards Board of the state after a study by Technical Safety Services, which recommended that nitrous oxide performed similarly as that of SF6 and safety of the worker will not put to jeopardy.
Source: http://www.ucsd.edu/