John Gruber of Mount Pleasant Township has worked in construction for 35 years. He's built sidewalks, driveways, all sorts of things.

	Tony Tye, Post-Gazette John Gruber's knees are still in bandages from the third-degree burns he suffered while kneeling in cement he was trying to mix to the proper consistency. Click photo for larger image.

So when his brother-in-law last month asked him for help in expanding a bathroom, he pitched in.

Gruber, 53, showed his brother-in-law and others how to mix the first batch of water, sand and portland cement to make concrete. Then the others took over mixing.

"Everybody was kind of an amateur," he said about the project on July 17. "Each batch got increasingly wetter and wetter. It was wetter than it should have been."

As a result, Gruber spent four hours kneeling in the mixture as he worked to make it the right consistency so it would set properly.

He didn't think anything of the experience until he took off his jeans, which were soaked with the mixture, and saw that his knees had turned black. He showered, went to bed, and returned the next day to put down ceramic tile.

But two days later his knees were so sore he could barely walk. The cement had caused third-degree burns on both of his knee-caps.

Cement burns, surprisingly, are a common injury seen by doctors at West Penn Hospital's Burn Unit, especially during summer months, when a lot of construction projects are under way. Mercy Hospital burn doctors also see their share, although most are related to industrial accidents.

"Sometimes, it's professional cement people who have a leak in their boots or gloves. More often it's do-it-yourselfers who are unaccustomed to using cement," said Dr. Harvey Slater, medical director of West Penn's burn unit.

Wet cement contains alkaline compounds such as lime (calcium oxide) that are corrosive to human tissue, with a pH level equivalent to that of oven or drain cleaners.

"As it sets, it gets hot, so there is a combination of a heat injury and chemical injury," Slater said. "It is insidious. The patient is rarely aware that the cement is on the skin until the damage is done."

Usually the burn unit sees patients who have been splashed with wet cement, bearing tiny areas of third-degree burns, the most severe kind that damage deep layers of the skin. Gruber's were unusual because they covered such a large area.

Doctors cut away the dead skin and took skin from his thigh to make grafts for his knees. He was discharged from West Penn last Tuesday, but recovery will take weeks.

"It's a significant injury," Slater said. "He can't kneel for many weeks to come."

Safety guidelines provided by Construction Safety Magazine and the Portland Cement Association call for anyone working with cement to wear rubber boots, alkali-resistant gloves and waterproof knee pads. Eye protection also is advised. Be aware that the mixture may get trapped inside rubber boots or gloves or gradually soak through coveralls.

Quickly remove any clothing contaminated with wet cement. And skin exposed to wet cement should be washed immediately with lots of cool, clean water.

Get medical attention if discomfort persists.

The mixture shouldn't pose a hazard for youngsters or others who make handprints in wet concrete on sidewalks, for example, as long as they wash off their hands right away.

Like Gruber, workers injured by the cement are usually shocked at how severe the injuries can be.

"It's a dangerous chemical," Slater said. "The damage is insidious and you won't know you're hurt until you're really hurt."