Ultraviolet radiation exposure in cannabis-growing facilities

Area of Science:

• Occupational Health and Safety
• Environmental Health
• Industrial Hygiene

Background:

• The cannabis industry, employing over 400,000 workers in the US, utilizes both natural and artificial light sources for cultivation.
• These light sources emit ultraviolet radiation (UVR), a known health hazard, yet worker exposure levels in cannabis facilities remain unstudied.
• Understanding UVR exposure is critical for safeguarding worker health in this rapidly expanding industry.

Purpose of the Study:

• To assess worker exposure to UVR in various cannabis cultivation and processing facilities.
• To identify the primary sources of UVR exposure for workers.
• To compare measured exposures against established occupational exposure limits.

Main Methods:

• Conducted UVR exposure assessments across five cannabis facilities in Washington State (indoor, outdoor, shade house).
• Performed lamp emission testing for various artificial lighting types.
• Measured worker UVR exposures during 87 work shifts, recording activities and personal protective equipment (PPE) usage.

Main Results:

• Average UVR irradiances varied significantly by lamp type, with germicidal lamps showing the highest emissions.
• Thirty percent of monitored work shifts exceeded the American Conference for Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV) for UVR.
• Outdoor solar radiation was the primary source of elevated UVR exposure for workers, particularly those working outdoors.

Conclusions:

• Outdoor cannabis workers face the highest risk of exceeding UVR exposure limits, emphasizing the need for sunscreen and appropriate PPE.
• While artificial lighting in this study did not substantially contribute to measured exposures, some lamps have the potential to exceed TLVs.
• Employers should prioritize low-UVR emitting lamps for indoor operations and implement engineering controls, especially for germicidal lamps, to mitigate worker exposure.