Vape Shop Employees Exposed to Detectable Levels of Diacetyl, 2,3-Pentanedione

Published January 10, 2018

Employees in a vape shop were exposed to detectable levels of two widely used flavoring chemicals, diacetyl and 2,3-pentanedione, according to a new report from the NIOSH Health Hazard Evaluation Program. The shop sells e-cigarettes and e-liquids, which are typically made up of propylene glycol, vegetable glycerin, nicotine, and flavoring chemicals. NIOSH staff visited the facility at the request of the vape shop owner, who was concerned about employees’ potential exposure to vaping chemicals.

All measured concentrations of diacetyl and 2,3-pentanedione were below occupational exposure limits, including NIOSH’s recommended exposure limit for diacetyl, 5 ppb, and its REL for 2,3-pentanedione, 9.3 ppb. NIOSH measured diacetyl in the air via evacuated canisters, a sampling method that doesn’t measure exposures as low as 2.6 ppb, the agency’s action level for diacetyl, so some of the personal air sampling results for diacetyl could have exceeded the action level. In workplaces where diacetyl exposures are above the action level, NIOSH recommends implementing engineering and work practice controls to keep exposures below the 5 ppb REL and developing a medical surveillance program.

In hand mixing custom e-liquid blends according to a customer’s taste, nicotine, propylene glycol, and vegetable glycerin preferences, employees are also potentially exposed to concentrated levels of liquid nicotine. NIOSH staff observed that not all employees wore chemical protective gloves when handling liquids containing nicotine and that a bottle of stock nicotine solution was stored in the same refrigerator with employees’ food. NIOSH urges the employer to ensure that workers wear nitrile gloves when handling liquids that contain nicotine, and that nitrile gloves, a long-sleeve laboratory coat, and goggles are worn when employees handle the stock nicotine solution. Because nicotine can break through glove material in six to nine minutes, NIOSH recommends enforcing a policy that requires employees to use a new pair of gloves each time they begin a new task involving nicotine. The nicotine solution should be stored away from food in a separate, clearly labeled refrigerator.

NIOSH’s air sampling results also showed concentrations of formaldehyde and acetaldehyde, another flavoring chemical, that were all below occupational exposure limits. The agency further reported very low levels of some surface contaminants, including chromium and nickel, which have previously been found in e-liquids and in vapor from e-cigarettes. NIOSH staff attributed these low levels to the effectiveness of cleaning practices in the vape shop. According to the agency’s report, employees wiped down commonly touched surfaces several times throughout the day.

While measured concentrations of diacetyl and 2,3-pentanedione were below all applicable OELs, NIOSH urges the employer to implement a policy to prohibit vaping in the shop with e-liquids containing those two flavoring chemicals.

“Flavoring chemicals such as diacetyl and 2,3-pentanedione have been associated with serious respiratory disease,” the NIOSH report reads. “One way to reduce exposure to these chemicals is to not use products containing them.”

Read the full report on NIOSH’s website (PDF).