Making Power and Pesticides Safer Through Risk Analysis

Exponent Presents at The Society for Risk Analysis Annual Meeting

December 10 - 14, 2023
Consultants analyze data on laptop screen. Exponent engineers perform quantitative risk assessment for buildings and structures.

Successful risk management requires the latest technical insights and approaches to mitigate hazards and liability — whether manufacturing safer pesticides or reducing outages and ignition dangers in utilities operation.

Explore leading-edge risk analysis techniques and quantitative risk assessment approaches at the Society for Risk Analysis Annual Meeting, where Exponent's speakers from our Buildings & Structures and Chemical Regulation & Food Safety practices will present their latest findings.

View of two utility poles and wires from the ground against a clear blue sky

"A Probabilistic Method to Assess the Risk of Contamination-Induced Insulator Flashover"

WEDNESDAY, DEC. 13 | 8:30-10:00 A.M.

Speaker: Gitanjali Bhattacharjee, Ph.D., Associate, Buildings & Structures

In electrical transmission and distribution networks, insulators prevent the flow of current from overhead conductors to supporting structures. Over their decades-long service lives, insulators are exposed to atmospheric pollution — including sea and road salts, byproducts of agricultural, construction, and industrial activity, and bird feces — that accumulates on their surfaces. When wetted by fog or light rain, salts in built-up contamination may dissolve, forming a conductive pathway on the insulator's surface. This can lead to flashover, insulator damage, power outages, and ignitions. For large power companies, regularly washing all insulators may be infeasible. Prioritizing insulators for washing is therefore critical to reducing the risks associated with contamination-induced insulator flashover (CIIF). This presentation will discuss a probabilistic framework for predicting the rate of CIIF given site-specific rates of contaminant accumulation and critical moisture events and the contamination's composition. 

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A hand holding a yellow spray container misting plants with pesticide

"Estimating Interspecies Pharmacodynamic Data-Derived Extrapolation Factors for Organophosphate Pesticides"

Speaker: Rick Reiss, Sc.D., Group Vice President and Principal Scientist, Chemical Regulation & Food Safety

Risk assessments for organophosphate (OP) pesticides can be refined by bridging the extrapolation from rat toxicity data to humans. One methodology to understand potential rat versus human differences is to measure and compare the rate of inhibition of OPs or their active metabolites with acetylcholinesterase (AChE). AChE inhibition is considered the most sensitive endpoint for OP regulatory risk assessment, and a key factor in the potency of a particular OP is the rate of inhibition of the OP or its active metabolite with AChE. An in vitro test system was used to measure the IC50 (concentration resulting in 50% inhibition) for a series of OPs or active metabolites with AChE derived from rat or human red blood cells (RBCs).

This poster will explain how, applying U.S. EPA guidance, the ratio of the rat to human IC50 can be used to estimate data-derived extrapolation factors (DDEFs) to replace the default interspecies uncertainty factor. This would represent the first time an in vitro method was used to modify pharmacodynamic uncertainty factors for most members of a class of chemicals. 

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