Table 1.

Characteristics of Ohio census block groups by the presence of Class II (CII) injection wells ($n=\mathrm{9,205}$), from 2010 to 2016. Data are medians (25th–75th percentiles) or n (%).

Characteristic	CII Well within Block Group ($n=156$)	No CII Well within Block Group ($n=\mathrm{9,049}$)	p-Valuea
Median age (y)	42.8 (39.5–47.5)	40.2 (33.9–46.2)	$2.1\times {10}^{-6}$
Population density (${\text{people}/\text{mi}}^2$)b	71.2 (40.1–157)	2,210 (433–4,750)	$<2.2\times {10}^{-16}$
Median income ($)	49,097 (41,333–57,050)	46,250 (33,100–61,944)	0.36
Education $\ge \text{high}\text{school}$ (%)	88.6 (84.3–92.6)	89.9 (82.6–94.9)	0.58
White only (%)	98.1 (95.3–100.0)	92.1 (74.7–97.7)	$2.2\times {10}^{-16}$
Voter turnout (%)	71.6 (68.1–75.2)	71.8 (64.1–76.4)	0.0017
Median household value ($)	118,750 (91,625–147,700)	109,800 (78,600–153,800)	0.36
Land area (${\mathrm{km}}^2$)	43.5 (25.4–74.3)	1.35 (0.51–7.43)	$<2.2\times {10}^{-16}$
Water area (${\mathrm{km}}^2$)	0.16 (0.02–0.58)	0.00 (0.00–0.04)	0.041
Utica Shale	124 (79.5%)	3,979 (44.0%)	$<2.2\times {10}^{-16}$
Marcellus Shale	42 (26.9%)	456 (5.0%)	$6.9\times {10}^{-9}$
Any UNG well	23 (14.7%)	161 (1.8%)	$1.1\times {10}^{-5}$

^aDifference between block groups with and without CII injection wells, two-sample t-tests.

^bEach unit of ${\text{people}/\text{mi}}^2$ is equivalent to $0.386{\text{people}/\text{km}}^2$.