An exposure and risk assessment is required for chemicals assigned Benchmark 1 or ToxFMD® for LPC Not Acceptable hazard classifications. In order to conduct such an assessment, data regarding the chemistry of these chemicals and the materials they comprise, how the chemicals and products containing them are manufactured, and the ultimate environmental fate of said chemicals as well as how the product is used and what types of personal protective equipment (PPE) the manufacturer recommends will be considered.
Chemical and Material-Specific Considerations
For each chemical that an exposure and risk assessment is being conducted, the scientist/risk assessor should have an understanding of the characteristics and manufacturing process for the chemical and material it comprises to determine if they may contribute to worker or consumer exposure to harmful chemicals during production, use, and final disposal or reutilization in a subsequent production stream.
Matrix Structure
The base material matrix (i.e., base polymer, metal alloy, natural fiber etc.) is used to judge whether chemical additives are able to freely migrate into external systems. For example, certain materials in indoor use applications may release volatiles contributing to poor indoor air quality, so emissions must be verified. Careful consideration is given to the type of matrix when making material assessment decisions.
Reaction Chemistry
Because materials are assessed based on the final state of all inputs to that material, it is important to have an in-depth understanding of the key chemical reactions taking place in a system and whether the chemical is still in its original form after curing or other reactions reach equilibrium. Collecting important chemical function data from the supply chain technical staff is a good way to gain understanding about the full picture of the complex chemical mixtures present in the final material or product in order to give the most accurate assessment rating.
Physicochemical Properties
General principles surrounding the physical and performance properties of chemicals impact the material assessments decisions in some cases. Some examples are as follows:
- Solubility – a chemical may be considered less aquatically toxic if it is insoluble in water. Alternatively, highly water soluble compounds may have limited dermal penetration potential.
- Volatility – if a chemical is known to volatize completely during manufacture, it is assumed to be present at less than 100 ppm of the final material or product.
- Structure stability – an example where structural stability overrides hazard ratings for ingredients is shown with spinels, which are often used in colorant applications, and are virtually indestructible compounds.
Process, Synthesis, and Manufacturing
It is well-known that process-related aspects of manufacturing and production can often pose just as much risk to human and ecological health as the products that are produced, by way of water effluent discharges, use of hazardous intermediate chemicals, and worker safety.
Exposure Route Considerations
Prediction of possible likely exposure scenarios lends guidance to decision-making as part of a risk assessment. Examples of possible exposure routes are:
- Occupational: including inhalation, oral (consider potential both direct and indirect), dermal/membranes.
- Consumer use: includes, inhalation, oral (consider potential for both direct and indirect), dermal/membranes.
- End-of-Use Phase Concerns: It is imperative to consider the end-of-use phase of products. Ideally, exposure scenarios will not lead to unintended risk to humans or the environment at any stage, including at the end-of-use. Some considerations to keep in mind when assessing the chemical composition of materials are as follows:
- Methods of disposal (i.e., deposits to water or soil by any method).
- Recyclability impacts.
- Incineration products and by-products.
- Atmospheric impacts (greenhouse gases and ozone depletion).
- Ecological impacts.
Manufacturer Recommendations for PPE and Safety Documentation
The TPP should consult the product SDS and other documentation (e.g., label and instruction manual) for recommendations regarding recommended PPE usage for the installer and/or consumer. The use of proper PPE may preclude exposure to hazardous chemicals, thereby lowering the risk of adverse health impacts. For occupational exposures, communication with the manufacturer and primary suppliers is required to identify the physical form of the chemicals used in the production stream, as well as any PPE and engineering controls used during production.
Modification of Risk Following Exposure Assessment for Consumers, Workers, Ecological Receptors
If the Material Health Assessor can demonstrate that significant consumer exposure is unlikely following anticipated use(s) of the product, then the risk of adverse effects to human health posed by Benchmark 1 or ToxFMD® for LPC Not Acceptable chemicals may be reduced relative to that anticipated from the hazard ratings alone. Similarly, if no occupational exposure is possible at the manufacturing site or for installers based on engineering controls or PPE used or anticipated to be used based on directions from the manufacturer, no risk of adverse effects to human health is anticipated from the product under review.
To demonstrate a lack of significant adverse risks to the environment (applicable for PBT, vPvB, or vPvT chemicals), the manufacturer must demonstrate a lack of direct release of the pertinent chemicals to the environment during manufacturing as well as during final disposal via take-back and/or recycling programs. If these conditions are met, the TPP may assign a risk rating of “LPC Acceptable”for the Benchmark 1 or ToxFMD® for LPC Not acceptable chemical(s) under review. However, if exposure to workers or consumers to the Benchmark 1 or ToxFMD® for LPC Not acceptable chemical(s) is possible or if a PBT, vPvB, or vPvT chemical(s) may be released to the environment during the course of the product manufacturing or lifespan, the risk rating is assigned as “LPC Not Acceptable.”
