The crisis in Flint, Mich., over lead in the city’s water supply has many focusing on the long-term effects of lead exposure for children there. Lead exposure in childhood can have lifelong consequences. The Centers for Disease Control and Prevention emphasize that preventing exposure is critical, but so are prompt efforts to mitigate lead’s effects. Here are some common questions about lead and lead poisoning.

How Are People Exposed to Lead?

In 1978, lead was banned in paint and other consumer goods made and sold in the United States. But lead paint in old buildings remains one of the most common sources of lead exposure for both children and adults, often from the dust that may remain even after surfaces have been stripped or painted over.

Other sources include:

• Soil contaminated with lead or food grown in it

• Lead water pipes or those soldered with lead, which can leach into the water supply

• Some canned goods, if the cans are soldered with lead

• Paint on some imported toys

• Some jewelry

What Are the Symptoms of Lead Exposure?

Low levels of lead exposure usually have no obvious or immediate symptoms, which means it can go undetected. But over time, even low levels of lead in blood can have profound effects on the brain and nervous system. Lower intelligence, difficulty in paying attention and with fine motor skills, and lower academic achievement have all been connected to elevated lead levels. Some studies have also linked lead exposure to violent behavior, and higher crime rates that can span at least two generations.