Table 2. Effect of fracturing on infant health.

Each coefficient and SE (shown in parentheses) is from a different regression and represents the effect on the given infant health outcome of in utero exposure to fracturing (when conception occurs after well spud date) within the indicated distance. The data sources for the regression are all birth certificates issued in Pennsylvania from 2004 to 2013 and the Pennsylvania DEP Internal Operator Well Inventory. We calculate the distance between maternal residence and well sites using Vincenty’s formula. The infant health index ranges from 0 to 1; an increase indicates better health. Each regression specification includes region of maternal residence*year FE, year*month of birth FE, and county of maternal residence FE. The following demographic controls are also included: mother is married, marital status missing, maternal race and ethnicity (black, Hispanic, missing), maternal education (no HS, HS diploma, some college, college, advanced degree, missing), maternal age (<20, 20 to 24, 25 to 29, 30 to 34, 35+, missing), child is male, child sex missing, and child parity (first, second, third, fourth born and higher, parity missing). Where indicated, we include a vector of maternal ID fixed effects (“mother FE”). “Under 15 km” indicates the subset of mothers living less than 15 km from the nearest well site. SEs are clustered on maternal ID. +P < 0.10; **P < 0.05; ***P < 0.01.

Dependent variable(Near, 0–1 km) × after(Near, 1–2 km) × after(Near, 2–3 km) × after
(1)(2)(3)(4)(5)(6)(7)(8)(9)
Low birth weight
(mean, 0.065)
0.016**
(0.007)
0.015**
(0.007)
0.012
(0.014)
0.006+
(0.004)
0.005
(0.004)
0.004
(0.007)
0.009***
(0.003)
0.008***
(0.003)
0.007
(0.005)
Birth weight
(mean, 3319.6)
−38.654**
(15.558)
−36.707**
(15.595)
−13.034
(31.137)
−3.534
(8.487)
−2.023
(8.530)
−10.439
(14.349)
−7.092
(6.515)
−5.294
(6.515)
0.803
(10.608)
Health index
(mean, 0.000)
−0.054***
(0.019)
−0.052***
(0.019)
−0.004
(0.040)
−0.020**
(0.010)
−0.018+
(0.011)
−0.018
(0.020)
−0.028***
(0.008)
−0.025***
(0.008)
−0.015
(0.015)
n1,086,917231,578231,5781,102,424247,085247,0851,117,919262,580262,580
Mother FENoNoYesNoNoYesNoNoYes
Under 15 kmNoYesYesNoYesYesNoYesYes