Is Nitrous Oxide scavenging required by law?

The assistant looked concerned as she posed this question to me. You see, she was pregnant and visibly worried about it. I explained that my understanding was that it is NOT required, but is HIGHLY recommended. I told her that if I were pregnant I would not work in an operatory that did not fascillitate Nitrous Oxide scavenging. I told her that I would try and figure out what the actual agency suggestions were:


“The Occupational Safety and Health Administration (OSHA) does not currently regulate nitrous oxide.”


“The National Institue for Occupational Safety and Health (NIOSH) has established a recommended exposure limit (REL) for nitrous oxide of 25 parts per million (ppm) parts of air (45 milligrams per cubic meter (mg/m(3))) as a time-weighted average (TWA) for the duration of the exposure [NIOSH 1992]”


“The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned nitrous oxide threshold limit value (TLV) of 50 ppm (90mg/m(3)) as a TWA for a nominal 8-hour workday and a 40-hour workweek [ACGIH 1994, p. 28]”

*Porter Instrument Company, Inc.

“WARNING: Dental workers are exposed to Nitrous Oxide (N2O) during administration of N20/O2 conscious sedation analgesia. NIOSH has recommended the exposures should be minimized. Contact NIOSH (1-800-35-NIOSH) to receive NIOSH Publications on Control of Nitrous Oxide in Dental Opertories. Exposure can be minimized by effective controls. National Institute for Occupational Safety and Health (NIOSH) publications state that controls, including System Maintenance, Ventilation and Work Practices can effectively reduce N2O concentrations in dental operations. Your Porter Scavenger
System is an important part of the system of controls.”

*Rationale for Limits

“The NIOSH limit is based on the risk of reproductive system effects and decreases in audivisual performance [NIOSH 1992].”

“The ACGIH limit is based on the risk or reproductive, hematological, and nervous system effects [ACGIH 1991, p. 1137]”

Quickly following the first question was the next, “Is there a way to test if I am being exposed to Nitrous Oxide?” Honestly, I had heard about offices that had used a badge to monitor Nitrous exposures, but was un-sure where to order them, so I told her I’d do some research on that as well. Here is what I’ve found:

Environmental Monitoring Technology
EMT, Inc.
121 Shivel Drive
Hendersonville, TN
(800) 284-2785
(615) 824-0712
(615) 822-5989 FAX

They sell Nitrous Oxide Monitoring Kits.
NIT001 – 1 badge – $50.00

Here are some other helpful websites that have information on the topic of Nitrous Oxide:

OSHA Nitrous Oxide Guidelines

NIOSH Nitrous Oxide Guidelines

ACGIH Nitrous Oxide: TLV documentation

Porter Instruments “Is Nitrous Oxide safe?”

“Nitrous Oxide Safety” by Fred Quarnstrom, DDS, FAGD, FASDA, FICD, American Board of Dental Anestesiology, Certified Consultant, American Association of Dental Consultants