First it was lead. Now it's a likely carcinogenic chemical.

Newark has again violated a federal standard, allowing a potentially cancer-causing contaminant to flow through the drinking water -- and the water it sells to nearby towns, according to state test records.

The state records show Newark's water contains high levels of haloacetic acids, a group of five possibly carcinogenic chemicals that are byproducts of the water disinfection process. People exposed to elevated levels of haloacetic acids for years are at an increased risk of getting cancer, according to the U.S. Environmental Protection Agency.

The test results deal yet another blow to public trust in Newark's water system.

The city is already under pressure to address elevated levels of lead in its drinking water and recently acknowledged it wasn't properly treating the water for corrosive properties at one of its plants.

The elevated levels of haloacetic acids are not considered an acute public health emergency by state and federal authorities, according to Kareem Adeem, the city's deputy director of water and sewer utilities.

He said Newark is aware of the high levels of haloacetic acids and is working to solve the problem. Specifically, Adeem said the city is making changes to its disinfection process and instituting a flushing program to remove old water from the system more quickly.

He said there were no additional problems with how the department was treating its water. He said "recent increases in organic material in source water and demands for higher chlorine dosages" caused a recent spike in haloacetic acids.

At least one water expert disagrees.

"The answer is for the city to get its act together," said Erik Olson, a drinking water expert for the Natural Resources Defense Council, an environmental advocacy group. The NRDC has also sued the city and the New Jersey Department of Environmental Protection over Newark's "dangerously" high levels of lead.

Chlorine is added to water supplies to clear them of bacteria. Olson said haloacetic acids are created when chlorine reacts with natural matter like leaves in the water. Having elevated levels of haloacetic acids is indicative of problems with how Newark is disinfecting its water, he said. The disinfection process, he said, needs to be adjusted so fewer of the acids are produced.

The maximum acceptable levels of haloacetic acids in drinking water, according to federal standards, is 60 parts per billion. The water coming from Newark's system, based on an average of the last four quarters, has halocetic acid levels as high as 81 parts per billion in one testing site.

Of the city's 12 testing sites, eight recorded elevated average levels of haloacetic acids. One of those sites: Newark's Health Department building on Williams Street.

Surrounding towns affected

More than 270,000 Newark residents drink the city's water that comes from two sources, the Wanaque Water System and the Pequannock Water System.

Pequannock serves every part of Newark except for the city's East Ward.

The elevated levels were found at various test sites around the city and not at the treatment plants.

Eight municipalities buy all or some of their water from Newark to serve their own residents. Those towns are Bloomfield, Belleville, East Orange, South Orange, Nutley, Liberty Township, Raritan and Pequannock Township. At least 500,000 customers are served by the Newark water system, according to the EPA.

Towns like South Orange and Raritan only purchase Newark water during emergencies. East Orange said it hasn't purchased water from Newark in 18 months and will only do so in extreme circumstances.

New Jersey American Water, which operates the water systems in Liberty and Raritan, said its water supply was not affected.

Belleville exceeded the federal standard for haloacetic acids in June and again in September of this year, records show. Bloomfield has violated the standard repeatedly since 2017.

"This mayor, this council, me as the administrator and the engineers, we are very, very concerned," Bloomfield's township administrator Matthew Watkins said. He said the township was "addressing our problem holistically" and has invested $10 million in improving its water system.

In the township's September public notice, informing residents of the presence of the contaminants, officials said they were working on building their own water pump.

Watkins said the intent of building a new facility was to save money. It should be operational by 2020 with the goal of supplying 75 percent of the town's water.

"Now, the water quality is obviously an issue," Watkins said. "We'd like to think that Newark is taking responsible action to correct the situation."

Belleville officials did not immediately return a request for comment.

Elevated levels of haloacetic acids have been found in water systems across the country.

Previous problems

The NJDEP's Bureau of Safe Drinking Water determined that Newark's water violated the standard on Oct. 3, and officially issued a violation on Nov. 1.

This is not the first time that Newark's water has been found with elevated levels of haloacetic acids. According to NJDEP Spokesman Larry Hajna, the city has violations dating back to the fourth quarter of 2003 up through 2005. Hajna added that the city was previously able to bring its water back into compliance.

The EPA learned of Newark's haloacetic acids violation this week but had not taken any enforcement action, according to spokeswoman Tayler Covington. She added that enforcement is up to the NJDEP.

Newark is preparing to send letters to affected residents on Nov. 4 notifying them of the elevated levels of haloacetic acids, as required by the state, according to Adeem. The city must also submit a plan to address the contamination within 30 days of receiving the violation from NJDEP, and the city has one year from the violation date to bring its water system into compliance.

The coming public notification only compounds questions about Newark's drinking water quality, as the city is also dealing with elevated levels of lead and distributing filters to affected residents.

The city has blamed the lead issues on aging service lines and is in the process of replacing them over the next eight years. But the problem is two-fold. Earlier this month, city officials acknowledged its corrosion control treatment to reduce the water's corrosive properties at the Pequonnock plant was no longer effective. As water corrodes and eats away at the aging pipes, lead can leach into the water.

Newark officials have maintained there is nothing wrong with the water they are supplying, or the water mains that distribute it.

Haloacetic acids, sometimes called HAAs or HAA5, include five chemicals that are byproducts of chlorine disinfection. The five chemicals are dichloroacetic acid, trichloroacetic acid, chloroacetic acid, bromoacetic acid and dibromoacetic acid.

Adeem noted that haloacetic acids are "possibly carcinogenic to humans because of evidence of carcinogenicity in laboratory animals and limited evidence in people." According to the nonprofit Environmental Working Group, haloacetic acids have been linked to bladder cancer in humans as well as liver cancer in animals.

Vulnerable populations, like pregnant women, are particularly at risk from haloacetic acids according to Tasha Stoiber, a senior scientist for Environmental Working Group, a non-profit that advocates for stricter drinking water standards.

"I think for vulnerable populations, I would be cautious since disinfectant byproducts in general can be very harmful during pregnancy," Stoiber said.

If the haloacetic acids levels were a health emergency, Adeem said that the public would've been notified within 24 hours. But since this is not considered an emergency, he said, the notices did not go out when the city learned of the violation in early October.

"If I was a consumer, I would probably want to know as soon as possible," Stoiber said.

Read more:

Newark said it was fixing the lead in its water. Now there's a problem with the treatment.

Getting lead out of Newark's tap water? That'll take $60M, and 8 years

Pipes in N.J. city were installed in the 1880s. There's lead in them, and it's a problem.

[Editor's note: This story has been updated to clarify that South Orange and East Orange only purchase Newark water during emergencies.]

Read more of NJ.com’s coverage of New Jersey water issues here.

Karen Yi may be reached at kyi@njadvancemedia.com. Follow her on Twitter at @karen_yi or on Facebook.

Michael Sol Warren may be reached at mwarren@njadvancemedia.com. Follow him on Twitter @MSolDub. Find NJ.com on Facebook.