Public concern about bisphenol A reached a tipping point several years ago. Cities, stores, even the Canadian government began banning or phasing out reusable water bottles and children's products that were made using the chemical.

BPA is an endocrine disruptor. Some scientists and health researchers suspect that the chemical is linked to a broad range of health issues, including developmental problems in children and reproductive problems later in life.

For Rochesterians, the issue hit close to home. Some of the plastic bottles in question were made by Nalgene, a Penfield-based arm of Thermo Fisher Scientific. Local and national concern surged and the company, responding to market pressures, began making its bottles out of a different plastic: one that didn't contain BPA.

But BPA is only one of a plethora of chemicals and pollutants that, though unseen or unnoticed, can have significant effects on public health. Diesel truck exhaust can affect breathing air, while lead paint dust is linked to developmental delays and a host of other problems.

Those relationships are the driving force behind environmental health campaigns locally, regionally, and nationally. Many of the campaigns focus on fetuses and children, since that's when environmental factors have their greatest impacts on a person's health.

"From the perspective of researchers, I think that looking at the exposure of fetuses and young children to environmental contaminants is an increasingly important theme," says Katrina Korfmacher, an associate professor in the University of Rochester's Department of Environmental Medicine.

There are three environmental health issues that are of immediate concern to local and state advocates and researchers: lead exposure, air quality, and the nation's chemical policy. And all have seen recent, significant developments, whether statistical, financial, or and public policy.

Since at least the mid 1990's, community leaders and health officials have fought to bring down and keep down the number of Monroe County children exposed to lead.

Part of that effort has been a partnership between government, health, medical, and community representatives. The Coalition to Prevent Lead Poisoning formed in 2000 and has conducted education and advocacy work around lead exposure. Its work, combined with changes in public policy and the law, led to an 85 percent decrease in reports of Monroe County children with elevated levels of lead in their blood, says Elizabeth McDade, the coalition's program manager. There was, however, a slight uptick in 2010.

Lead exposure happens primarily through dust from lead paint, making it a housing issue, McDade says. Lead is linked to a long list of health problems, ranging from learning disabilities and behavior problems in children, to kidney damage and memory loss in adults. Lead accumulates in the body over time and there is no way to remove it.

"There are lifelong health deficits that go along with this," McDade says.

Anti-lead advocates worry that a recent budgetary decision by the county could jeopardize further progress in reducing lead exposure. The county used to require inspections of apartments and houses that were being rented to some public assistance recipients. It contracted with the city to do that work, which included lead inspections. The county ended the program in 2010, but extended the funding. The extensions end this spring, however.

The city, county, and coalition are looking for ways to collaborate on an effective inspection process, McDade says.

Advocates have made the city a focus because of the city's density and its older housing stock. The city's oldest areas are most likely to be populated by the poor, putting them at a greater risk of exposure.

At the national level, a Centers for Disease Control panel recently recommended lowering a key child lead-poisoning threshold. The panel recommended halving the lead concentration level at which doctors and public health officials should act. That could mean a large increase in the reported cases of children with elevated levels of lead in their blood.

Air quality has steadily improved across the country over the last few decades. In particular, particle pollution - fine soot, essentially - is less of a problem than it used to be.

The reduction in particle pollution is largely due to regulations that cleaned up diesel fuel. The fuel is about 90 percent cleaner than it was a decade ago, says Michael Seilback, vice president for public policy and communications for the American Lung Association in New York. The Clean Air Act also contributed.

But many metro areas still have ozone problems, including Monroe County. Ozone, a lung irritant, is formed through a combination of heat, sunlight, nitrogen oxides, and volatile organic chemicals. The last two are byproducts of fossil fuel combustion: making ozone largely a result of motor vehicle traffic.

Every year, the American Lung Association evaluates US counties' air quality based on several factors, including the number of high ozone days.

In 2011, the Lung Association gave Monroe County an F on ozone. Monroe had too many days when high ozone levels posed a threat to vulnerable populations, the report card said. Ozone can aggravate asthma, lung disease, and heart disease, and can be harmful to children and the elderly. It also disproportionately affects the poor.

"What this report shows us is, yes the air is cleaner and it's trending in the right direction, but based on the science, we know that there are too many days where that air pollution level is still too high and it's putting people's health at risk," Seilback says.

Air pollution can be tough to address, since it comes from many sources. For example, particulate pollution often comes from diesel engines or power plants, but it can also come from burning wood.

And New York may have to contend with additional emissions sources - of ozone-causing gases, greenhouse gases, and particle pollution - if the state green-lights shale gas extraction by high-volume hydraulic fracturing. Drilling-related diesel generators, diesel-powered compressor stations, and truck traffic could mean that non-industrialized areas with no previous air quality problems become major pollution sources.

And since emissions don't just sit in one place, the pollution is a regional issue. Researchers in Texas and Pennsylvania have projected substantial increases of ozone-causing gases in those regions. They've modeled the data based on known emissions figures from wells.

The Lung Association hasn't taken a position on fracking, but it does have concerns about the method's potential to degrade air quality. The association has asked the State Department of Environmental Conservation to be proactive about monitoring the emissions, and to require, to the extent possible, filtering and emissions-reducing technologies.

"What we're asking is that we ensure that any process that moves forward is putting health before a quick profit," says the Lung Association's Seilback.

Under federal law, companies don't have to prove that chemicals are safe before they put them on the market. That's a problem that's resulted in a variety of potentially harmful chemicals making their way into consumer products. BPA is one, along with classes of flame retardants.

Environmental health advocates, researchers, and politicians are pushing for reforms to the nation's chemical policy. Chemicals are regulated via the Toxic Substances Control Act, which was signed into law in 1976. There's been no significant action since.

"It was supposed to set up a process for evaluating chemicals and removing chemicals that were problematic: where scientific evidence showed that people were being harmed or that the environment was being harmed," says Bobbi Chase Wilding, deputy director for Clean and Healthy New York, an environmental health advocacy group.

But not all of that happened, she says.

When TSCA became law, it restricted the production, use, and disposal of PCBs, asbestos, radon, and lead-based paint. It grandfathered in 62,000 chemicals, however, including BPA and phthalates, both of which are used in the production of plastics.

There are now more than 80,000 chemicals in commerce, says Bernard Weiss, a professor in the University of Rochester's Department of Environmental Medicine. But regulators and researchers only have a great deal of information of about a half-dozen of them, he says, and some awareness about the effects of a handful of others.

"We just don't know very much about most of these chemicals in the environment," Weiss says.

Even though TSCA was supposed to empower the Environmental Protection Agency, the agency remains essentially powerless, Chase Wilding says. For example, the EPA tried to ban asbestos in 1990, but the industry sued and the agency lost. The EPA hasn't tried to ban anything since, Chase Wilding says.

Part of the problem is that even if research shows a chemical is unsafe, under the current law it's difficult to get that chemical off the market.

Some lawmakers have tried to change that. The federal Safe Chemicals Act, which would require companies to prove the safety of any new chemical before it's put on the market, is working its way through the Senate.

Due to lack of action at the federal level, states are starting to react. In 2010, New York legislators passed a law to start phasing out BPA in certain children's projects. Safer States, an advocacy group, says New York legislators might consider bills this year that would:

• develop a publicly-available list of chemicals of concern and require that manufacturers disclose when their products contain those chemicals;
• ban or restrict certain flame retardants;
• restrict formaldehyde in beauty products.

But the fact that states even have to act shows that the US needs a proactive approach to determining whether chemicals are toxic or unsafe, Chase Wilding says.

"With a system that's supposed to protect us so fundamentally broken and so fundamentally flawed, we think it's critically important that the law be reformed and strengthened so people aren't sitting around as guinea pigs," she says.