To answer this question in 3 common conditions, the California Birth Defects Monitoring Program interviewed over 2000 mothers, calculating distances from their homes to hazardous waste sites.

VERY CLOSE RESIDENCE RAISES RISK

Women who lived within 1/4 mile of a Superfund site during the first 3 months of pregnancy had a greater risk for having babies with certain birth defects:

	Conotruncal heart defects, a group of serious heart defects, were 4 times as likely (increasing from 1/1000 to 1/ 250 babies).
	Neural tube defects—spina bifida and anencephaly—were 2 times as likely (increasing from 1/1000 to 1/ 500 babies).
	Cleft lip and cleft palate occurred no more frequently than expected.

Women who lived farther than 1/4 mile from sites showed no higher risk.

ONLY A SMALL NUMBER OF FAMILIES AFFECTED

	Only 0.6% of the mothers interviewed lived within 1/4 mile of a Superfund site. About half of these women lived on military bases
	Hazardous waste sites were a possible factor in only a few birth defects cases: 8 of the 507 babies with neural tube defects and 3 of the 201 babies with heart defects.

IMPLICATIONS

	Although the small number of cases around hazardous waste sites means the findings don't have strong statistical power, they do support earlier research suggesting higher risk.
	Study findings—higher risk for certain birth defects among those living within 1/4 mile of Superfund sites—are relevant as communities plan to develop or re-use these sites.
	A central problem in studying hazardous waste sites is defining exposure. A woman living near a site may not actually have contact with its contents—airborne contamination diffuses rapidly as it travels from its source; groundwater contamination may never reach drinking water supplies. Further studies are not likely to yield more definitive answers unless they can incorporate direct exposure measures.

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