# Neurological Effects of Environmental Styrene and BTEX Exposure in a Gulf of Mexico Cohort

> **NIH NIH R01** · UNIV OF NORTH CAROLINA CHAPEL HILL · 2022 · $438,531

## Abstract

Abstract
Styrene is neurotoxic at occupational levels, but has received little study at environmental levels experienced by
the general population, despite widespread exposure. Our study team has found that annual average ambient
styrene levels are adversely associated with neurologic function and symptoms, including decrements in
visual, sensory, and vestibular function. Exposure to styrene in the general population occurs primarily through
inhalation of industrial and vehicle emissions, tobacco smoke, and off-gassing of building materials. It is produced
from petroleum-derived benzene and ethylbenzene, which explains why over half of US styrene production
occurs near oil and gas operations in the Gulf states. Benzene, ethylbenzene, toluene, and xylenes (i.e.,
BTEX) are also neurotoxic at occupational levels. The proposed study is significant because there are virtually
no data describing the safety of most of these neurotoxicants at general population levels, despite widespread
exposure. The objective of this study is to investigate the acute and chronic neurotoxicity of styrene and BTEX
at levels relevant to the general population. Our central hypothesis is that, even at general population levels,
higher ambient styrene/BTEX levels are associated with reduced peripheral nerve and neurobehavioral function
and increased neurologic symptoms. We will test this in a prospective, well-characterized cohort of 23,370 Gulf
state residents enrolled in the Gulf Long-Term Follow-up Study in 2011-2013—a socioeconomically
disadvantaged, medically underserved, and racially diverse population with significant unexplained health
disparities. This population has average blood styrene levels 2-3 times higher than those observed in the
general population, but much lower than the ~25-fold higher levels typically observed in occupationally exposed
populations. We have extensive information on all cohort members, from enrollment and follow-up interviews,
on demographic, lifestyle, occupational, and health factors; geocoded residential histories; measured blood
levels of styrene and BTEX from 965 cohort members during the last year of enrollment; and results of extensive
peripheral neurologic function and neurobehavioral tests administered to 3,403 members 2-4 years after
enrollment. We propose to: (1) Generate high resolution temporally- and spatially-referenced ambient (air)
styrene and BTEX concentrations in the Gulf region over a 6 year follow-up period, (2) Evaluate estimated
ambient styrene and BTEX concentrations against measured blood styrene and BTEX levels, and (3) Determine
associations of styrene and BTEX exposures, both individually and as a mixture, with neurologic symptoms
and neurobehavioral and peripheral neurologic function, accounting for other neurotoxic air pollutants. This
study is innovative because we will be the first to investigate the neurotoxicity of styrene at general population
levels and we will do so using state-of-the-art air quality ...

## Key facts

- **NIH application ID:** 10428541
- **Project number:** 5R01ES031127-03
- **Recipient organization:** UNIV OF NORTH CAROLINA CHAPEL HILL
- **Principal Investigator:** Bok Haeng Baek
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $438,531
- **Award type:** 5
- **Project period:** 2020-08-01 → 2024-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10428541

## Citation

> US National Institutes of Health, RePORTER application 10428541, Neurological Effects of Environmental Styrene and BTEX Exposure in a Gulf of Mexico Cohort (5R01ES031127-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10428541. Licensed CC0.

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