Sponsored by Chemscape Safety Technologies.

Cannabis production is an example of an industry where control banding guides the assessment and management of workplace risks for substances with no occupational exposure limits. The commercial production of cannabis is a new and rapidly expanding industry of small and medium-sized producers that typically lack access to occupational hygienists and have no exposure or toxicological data from which to estimate OELs.

Although cannabis is considered a food-grade pharmaceutical substance at the consumer end, the production environment, consisting of large greenhouses and process equipment, can present hazardous exposures for workers. Many workers have daily exposure to cannabis on a scale and frequency that can pose health hazards to their skin and respiratory systems. Toxic reproductive effects are also associated with the tetrahydrocannabinol (THC) and cannabidiol (CBD) components of cannabis.

Scenario 1: Control Banding of Cannabis (Hemp) Oil

Cannabis (hemp) oil extracted from cannabis seeds is used for cooking, aromatherapy, and natural perfumery. Section 2 from a cannabis oil safety data sheet, which identifies relevant hazard statements associated with the Globally Harmonized System for Classification and Labelling of Chemicals (GHS), is provided in Table 1. According to COSHH Essentials, a control banding scheme from the United Kingdom's Health and Safety Executive, cannabis oil is in Group C, the designation for substances that are "somewhat hazardous." Banding simplifies hazard communication, signaling to workers that the oil is a moderate-priority hazardous substance. The hazard band provides a concentration range of >0.5–5 ppm so that an IH can gauge whether exposure controls are appropriate, effective, and maintained.

Control banding of three different exposure profiles—also known as similar exposure groups (SEGs)—using COSHH Essentials generates three different control approaches (see Table 2). Personal protective equipment is part of the control approach for each level to reduce the potential for skin irritation and sensitization.

Scenario 2: Control Banding of Cannabis Plant

Cannabis plants are grown, harvested, and distributed as feedstock for cannabis consumables. The GHS classification from section 2 of an SDS for a cannabis plant is provided in Table 3. COSHH Essentials health hazard banding would classify this substance as Group D or “most hazardous.” This band signals a high-priority hazardous substance to workers, supervisors, and OEHS personnel. The concentration range for this band is <0.01 mg/m³ as a working criterion for verifying the applicability and performance of exposure controls.

Table 4 lists three different exposure profiles (that is, SEGs) with different control approaches. Containment features prominently because the substance falls into Hazard Group D. This level of control is more difficult in agricultural settings such as large greenhouses. Even engineering controls such as local exhaust ventilation, fume hoods, and ventilated work benches may be impractical for harvesting and monitoring growth. In these situations, the OEHS professional will typically rely on procedures that maintain low dust levels in large or outdoor workspaces with general ventilation and full PPE (including respirators, gloves, coveralls, and decontamination protocols). Refer to COSHH Essentials Direct Advice Sheets for industry-specific details.

The Value of Control Banding

Control banding offers an actionable plan in the absence of OELs. Implementing controls identified through a scheme like COSHH Essentials takes less time than creating a sampling plan or waiting for lab results. OEHS personnel can confirm exposure control by measuring the effectiveness of containment and engineering controls and adherence to PPE and safety policies. Using control banding transfers the bulk of industrial hygiene time, budget, and resources from anticipation, recognition, and evaluation toward higher-value control and confirm activities.