Now there's an investigation into allegations that the city tried to cover up the danger.
Angry activist groups say San Francisco's Health Department has gotten too cozy with Lennar, the developer promising to turn the old naval shipyard into a vibrant neighborhood.
Shops, housing and possibly a football stadium would line the new streets, but first Lennar has to clean up decades of toxic waste left on the street, which includes asbestos.
"It don't take a full cup of asbestos," said resident Vivian Donahue. "It takes one, one particle to come down into your lungs."
Donahue claims she's had chronic headaches and her grandson has suffered from nosebleeds since the cleanup started about a half-block from her home.
"We have been to the health department, and they tell us that it's nothing wrong with us," Donahue said. "And we know we're sick."
The health department has reported acceptably low levels of the dust, but a watchdog group filed a Freedom of Information Act request and obtained emails that show Lennar often reviewed those reports before they were present.
In one email, environmental engineer Amy Brownell told Lennar, "Go ahead and change any way you want. I may change some of it back but I'm willing to read your versions."
"Asking a developer, 'Here's what I want to say. You can re-write this in any way you want to, what do you want me to say?' All trust is lost," said Jaron Browne, a group activist spokeswoman.
Activists brought those emails to Supervisor David Campos, who convened the public hearing.
"I think that the emails raise serious concerns," Campos said. "You want complete objectivity by the department."
But those who support the development dismiss the concerns.
"The stuff that they're coming up with is just pure, plain-old paranoia," said Al Norman of the Bayview Merchants Association.
Norman claims the activists are simply anti-development and accuses them of trying to stop a project his neighborhood desperately needs.
"Get people back to work, to try to stop some of the killing and some of the other negative activities in the Bayview," said Norman.
The health department has launched its own ethics investigation, but the watchdog group wants an independent audit, especially of Brownell.
"Everything she had her hands on, everything she commented on, we want it revisited, reviewed and investigated," said neighborhood activist Leon Muhammad.
Amy Brownell wasn't at the hearing and declined ABC7's request for an interview. We asked for a statement from Lennar more than once, and each time we were met with a simple "No, thank you."