NIOSH logo and tagline

NIOSH Study Finds Widespread Use of Patient Nasal Scavenging Masks to Control Nitrous Oxide during Dental Procedures but Adherence to Other Recommended Practices Was Lacking

June 13, 2017
NIOSH Update:
Press Contact: Nura Sadeghpour (202) 245-0673

A new article from the National Institute for Occupational Safety and Health (NIOSH) found that scavenging systems, equipment used to prevent nitrous oxide gas from escaping into the dental operatory, are widely used but adherence to other recommended precautionary practices was lacking during dental procedures. This article was published in the June issue of the Journal of Occupational and Environmental Hygiene and is available online.

Results are derived from the 2011 NIOSH Health and Safety Practices Survey of Healthcare Workers, the largest federally-sponsored survey of healthcare workers in the U.S., which addresses safety and health practices relative to hazardous chemicals. This web-based survey is one of the first to examine adherence to precautionary practices among dental practitioners who administered nitrous oxide to adult and pediatric patients. Members of professional practice organizations representing dentists, dental hygienists and dental assistants were invited to participate in the survey. Survey responses were analyzed from 284 dental practitioners who administered nitrous oxide in the seven days prior to the survey and who were in private practice.

Most (>93%) respondents reported that they always used either a nasal scavenging mask or local exhaust ventilation (LEV) near the patient’s mouth when administering nitrous oxide. Nasal masks were by far the preferred method of control, always used by 96% of respondents for pediatric (P) patients and 91% for adult (A) patients. Adherence to other recommended practices were lacking to varying degrees, and were essentially no different by patient type. Examples of inadequate administrative and work practice controls which increase exposure risk, expressed as percent of respondents, included:

  • not checking nitrous oxide equipment for leaks (47% P, 51% A).
  • starting nitrous oxide gas flow before delivery mask or airway mask was applied to patient (14% P; 16% A).
  • not turning off nitrous oxide gas flow before turning off oxygen flow to the patient (8% P; 10% A).
  • lacking standard procedures to minimize occupational exposure (13% of all respondents).
  • lacking training on safe handling and administration methods (3% of all respondents).

Successful management of nitrous oxide should include nasal scavenging masks, supplementary LEV if needed, adequate general ventilation, regular inspection of nitrous oxide delivery and scavenging equipment for leaks, availability of standard procedures to minimize exposure, periodic training and medical surveillance.

The findings from this survey are expected to help NIOSH, partners, employers and healthcare workers better understand current health and safety practices relative to working with hazardous chemical agents, identify gaps in current knowledge about those practices, and, in collaboration with partners, design further research for addressing those gaps. To access the paper online, visit:

To learn more about healthcare worker safety and health, visit:

NIOSH is the federal institute that conducts research and makes recommendations for preventing work-related injuries, illnesses and deaths. More information can be found at