As discussed in yesterday’s Advisor, the National Institute for Occupational Safety and Health (NIOSH) recently released a draft guidance for more quickly categorizing workplace chemical exposures through banding. Today we will consider the potential use of the guidance for environment, health, and safety (EHS) managers.
NIOSH recently released a draft document outlining a process to apply occupational exposure banding to a broad spectrum of occupational settings to determine a potential range of chemical exposure levels that can be used as targets for exposure controls to reduce risk among workers.
Since hazard banding usually requires significant expertise in industrial hygiene, NIOSH has developed a three-tiered process intended to open up assessment process for wider usage.
This article will discuss Tier 1, which involves assigning an occupational exposure band (OEB) based on criteria aligned with specific Globally Harmonized System of Classification and Labelling of Chemicals (GHS) hazard codes (known as H-codes) and categories. It is intended for individuals with basic toxicology knowledge.
In general, Tier 1 can be used as a quick screening method, but NIOSH recommends going to Tier 2 if the user expertise is available. Tier 1 would likely be more be useful when banding a large number of chemicals and deciding which ones should be prioritized for elimination or substitution.
Note. NIOSH recommends 5 bands in the process: bands A to E, where band A is least severe and band E is most severe).
Five Steps in Tier 1
There are five steps in Tier 1 for assigning an OEB to a chemical:
- Determine that the chemical has no occupational exposure limit (OEL).
- Locate GHS hazard codes and categories in recommended databases.
- Compare GHS hazard codes and categories with NIOSH criteria for each health endpoint.
- Assign a band for each relevant health end point based on criteria.
- Assign a Tier 1 OEB for the chemical based on most protective end point band.
It should be noted that the NIOSH suggestions for the Tier 1 process skew toward caution. Bands A and B, the least severe with fewest restrictions, cannot be used in the Tier 1 process.
Using Tier 1: An Example
Here’s an example of how you would be able to band a chemical using the Tier 1 process.
This example uses chloral hydrate (CAS# 302-17-0), which has no OEL, so you can use the Tier 1 banding process.
Determine the three-digit H-codes and hazard categories assigned to the chemical by the GHS. These H-codes and hazard categories can be found in some databases, but the easiest source to use is an OSHA-compliant safety data sheet (SDS).
For chloral hydrate, the H-codes are H315, H319, and H301. The categories are Eye Irrit 2, Skin Irrit 2, and Acute Tox 3.
Note. The GHG 300-level H codes refer to health hazards.
Next, determine which OEB corresponds to each of the health-based (300-level) H-codes for that chemical. The OEBs for Tier 1 are on page 111 of NIOSH’s draft banding guide. Find the H-code on the chart, and find the corresponding OEB at the top of the column. If no H-code exists for a particular end point, that end point cannot be banded. Note: When H-codes correspond to more than one band, the hazard category is used to determine the end point specific band.
Finally, assign the overall occupational exposure band for the chemical based on the H-code(s) that is/are most protective based on the following rules:
- If no H-codes are available for the chemical, do not band in Tier 1.
- The overall band in a Tier 1 process is never less protective than band C.
- If the most protective H-code corresponds to both bands D and E, the hazard categories should be used to make the final determination. If the hazard category is not available, band E should be assigned.
For chloral hydrate, the most protective H-codes correspond to band C.