MORRISTOWN -- Initial testing at Morristown Medical Center last month showed the lead in the water at 100 Madison Ave. was 73 times greater than the federal action limit in one of the 39 samples tested.

Twenty-eight out of 39 samples tested by the hospital on Feb. 22 were above the federal Environmental Protection Agency's action limit of 15 parts per billion, Atlantic Health System said in a notice posted online.

The hospital, which has been issued two violations by the state Department of Environmental Protection in connection with its elevated lead levels, received a reading of 1,100 parts per billion at the hospital's Meade 1 unit on Feb. 22.

Three on-site locations also exceeded 700 parts per billion, according to testing by Accutest Laboratory: Goryeb Children's Hospital, a restroom in Simon B and the Simon A nursing station. Another seven locations exceeded 300 parts per billion.

Testing four days later by the Department of Health and a private lab, Garden State Laboratory still showed elevated lead levels at the majority of those sites -- though many were lower than the highest levels found during the Feb. 22 sampling.

Nearly a thousand people have been tested so far for lead exposure, but the hospital has not yet released its findings pending a review by the DEP and DOH.

Morristown Medical Center spokeswoman Elaine Andrecovich has said patients, guests and employees who ingested tap water at the 100 Madison Ave. location between Jan. 22 and Feb. 25 may have been exposed to lead.

"The people who have already been tested -- which consist of employees, children (including those from the day care), current and former patients, visitors, volunteers, and members of the public -- were either those in a high risk group (pregnant women or children under six who ingested water at the medical center from January 22- February 25), or those concerned due to their level of water consumption," Andrecovich said. "As we receive these results, we are notifying patients directly."

DEP spokesman Bob Considine has said the agency was advised by the licensed operator of the Morristown Medical Center water system on Feb. 17 that its corrosion control system had been offline for an undetermined period of time. That system, he said, is used to prevent lead that may be in pipes, solder and fixtures from leaching into the water.

The hospital then conducted its own sampling of tap water on Feb. 22 to determine the possible impact, and, on Feb. 25, advised the DEP and DOH as to its results, which ranged from no trace of lead to "well above" the EPA's action level of 15 parts per billion. Both the DEP and DOH then advised the hospital to go on bottled water for drinking and food preparation.

The possible root cause of the elevated lead numbers is the non-operation of the corrosion control system, according to the DEP. The raw water source didn't show any presence of contamination.

"With the system not in operation, the orthophosphate protective coating which prevents the lead from interacting with water, may have been compromised and allowed for the release of lead into the hospital's distribution system," Considine said.

The hospital was issued a notice of violation on Feb. 19 for the interruption in the operation of the corrosion control system, and a second violation was issued on March 2 for allegedly failing to update its organophosphate results between Feb. 9 and Feb. 16. No fines have been assessed at this point as the investigation is still continuing, he said.

It's still not clear when the hospital will return to tap water, but another round of testing is expected after the hospital's water system has been completely flushed, Considine said. Andrecovich said Thursday the hospital was still using bottled water for drinking and food preparation.

Andrecovich has said the hospital tests its water for lead on a semi-annual basis. The last time the hospital received acceptable water results was on Jan. 22, which is the baseline for the possible length of the contamination, she said.

The hospital has been reaching out to mothers who delivered at the hospital during this period since they're part of a "higher-risk population," she said.

A call center has been established at Morristown Medical Center at 855-635-4657 to answer any questions concerned patients, guests or vendors may have about the water supply, Andrecovich said. The call center will be open from 8 a.m. to 8 p.m.

"Outside of these hours, we ask that you speak with the NJ Poison Control Hotline at 1-800-222-1222, which is equipped to answer questions immediately," she said.

According to the Centers for Disease Control and Prevention, there is no safe lead level in children. Even at low levels, lead has been shown to affect intelligence, the ability to pay attention and academic achievement. Lead exposure can be dangerous for adults as well.

For children up to the age of 5, experts use a reference level of 5 micrograms per deciliter of lead in blood to identify children with elevated blood lead levels. In the past, blood lead level tests used a higher threshold of 10 micrograms per deciliter to identify elevated levels, which is the standard New Jersey still uses.

The CDC advises that children with blood lead levels greater than or equal to 45 micrograms per deciliter of lead in blood receive chelation therapy -- a treatment that's used to remove heavy metals or minerals from the body.

More information is also available on the CDC's website.

Justin Zaremba may be reached at jzaremba@njadvancemedia.com. Follow him on Twitter @JustinZarembaNJ. Find NJ.com on Facebook.