NEW YORK (CNN) -- Dr. Walter Friedel had successfully completed plenty of do-it-yourself projects around his New Jersey home. So when he bought Stand 'n Seal tile grout sealer from Home Depot in October 2005, he never imagined it might make him sick.
Dr. Walter Friedel says a home improvement product he purchased in 2005 gave him "chemical pneumonia."
Friedel said he read the instructions before using the product. As suggested, he ventilated the area. Yet a half hour after spraying Stand 'n Seal on the tile floor in his hot tub room, he said he could barely breathe.
"By the time I made it from my bedroom to the kitchen, I was down on one knee, I was so short of breath," he said.
Friedel said doctors told him a chemical in Stand 'n Seal had severely damaged 30 percent of his lungs. They said he had "chemical pneumonia" and put him in intensive care for four days. Friedel needed an oxygen tank for four months. He still struggles to walk up long flights of stairs or hills without shortness of breath, he said.
What Friedel didn't know before using the tile grout sealer was that it had been recalled by the Consumer Product Safety Commission two months earlier. News reports at the time said the product had made dozens of people sick and killed two of them.
The Consumer Product Safety Commission, a federal agency, is supposed to keep unsafe products off store shelves. But with just 400 employees -- half the number it had in 1973 -- monitoring about 15,000 products, unsafe products like Stand 'n Seal sometimes wind up in consumers' hands.
"The Consumer Product Safety Commission is a woefully underfunded, understaffed safety agency," said Don Mays, senior director of Consumer Reports. He also said the CPSC's lab equipment is outdated.
CNN tried to ask the CPSC about these charges, but a spokeswoman refused to comment, saying an ongoing investigation prevents the agency from discussing the issue.
Friedel and nearly 200 other victims are suing Home Depot along with Stand 'n Seal's manufacturer accusing them of manufacturing and selling an unsafe product.
Court documents show as far back as May 2005 consumers started complaining about Stand 'n Seal to its manufacturer, Roanoke, now known as BRTT.
In an internal e-mail dated June 17, 2005, company Chairman William Kyte wrote, "For the last two months or so we have been getting calls with problems related to the Stand 'n Seal. He called the situation "very serious."
The CPSC started an investigation in June 2005, but didn't recall Stand 'n Seal until the end of August, more than two months later.
"The Consumer Product Safety Commission clearly dropped the ball on the Stand 'n Seal case. They failed to get an unsafe product off the market," Mays said.
Records show Roanoke promised it had fixed the problem after the recall. The CPSC allowed Stand 'n Seal back on the market with a new formula. Friedel was able to buy the cans that made him sick two months after the recall.
The numbers on the cans Friedel bought and showed CNN did not match the numbers on the recall list.
"These were supposed to be safe cans," Friedel said.
A recall notice on the CPSC's Web site warns about Stand 'n Seal cans bought before June 2005. But it does not indicate that people like Friedel were able to buy the product and got sick from it long after the initial recall. An operator from the CPSC's public recall hotline told CNN that as long as we bought the product after June 2005, our cans would be safe.
Home Depot pulled the product off the shelves in March of this year. The company refused an interview, but it has denied liability, saying in a statement that it removed the recalled cans and was not aware that problems continued. The statement adds that Home Depot "never knowingly sold any of the recalled product."
Even though Friedel isn't suing the CPSC, he blames the commission in part for what happened.
"They didn't fulfill their job, that's for sure," Friedel said. E-mail to a friend
CNN's Catherine Mitchell contributed to this report.