Ocean swimmers at Myrtle Beach were exposed on more than 60 days last year to water pollution levels high enough to potentially cause health issues ranging from rashes and infections to gastrointestinal and respiratory diseases, a new report from a national nonprofit says.

The Environment America Research & Policy Center indicated that on the 74 days Myrtle Beach ocean water was tested last year, 61 days had pollution levels that posed potential health hazards to swimmers. Compared to the rest of the state’s ocean waters, Myrtle Beach ranked highest in the number of unsafe days, according to the study.

But local and state officials contend that the study’s chosen standard is too stringent. When the appropriate standard is applied, they said, the number of unsafe swimming days at Myrtle Beach drops significantly.

Under the guidelines used by the state Department of Health and Environmental Control, 26 of the 74 days examined had pollution levels high enough to cause illness, according to an analysis of department data by The State Media Co.

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But the research group said even that many days is “unacceptably high… in anyone’s book.”

The dispute isn’t over the amount of pollution found in the surf: both groups are analyzing the same numbers. Rather, the disagreement is over what level of pollution threatens swimmers’ health.

The research center uses a tool from the federal Environmental Protection Agency called “Beach Action Value,” defined as the most aggressive approach for protecting a person’s health. That standard is 60 “colony-forming units,” or cfu, per 100 milliliters. But the EPA says advisories aren’t required until the water tests for 110 cfu. DHEC issues warnings at 104 cfu.

DHEC and Coastal Carolina University combined to test the ocean water at Myrtle Beach on those 74 days last year. They gathered data from up to 13 sites on each of those days for a total of over 900 samples, according to DHEC data.

The Environment America Research & Policy Center looked at the level of fecal indicator bacteria levels — human and animal waste that can sicken people who come in contact with it in high concentrations. The bacteria, enterococcus, is the only bacteria that can cause beach advisories. In excess, fecal material in the water is associated with higher rates of illness in people, said DHEC spokeswoman Laura Renwick.

The ocean water at Myrtle Beach gets polluted after heavy rains hit highly developed areas. Instead of being absorbed by nature, the water runs off roadways, pavement and parking lots, picking up pollutants along the way. In some spots, large drain pipes dump stormwater runoff onto the beach and into the ocean.

Runoff that seeps into the surf can contain pathogens that threaten swimmers’ health, including skin rashes, gastrointestinal and respiratory disease, and ear and eye infections. Ingesting the specific bacteria, enterococcus, doesn’t mean a swimmer will get sick, but exposure increases the chances of becoming ill.

Under the Beach Action Value, the research and policy center found Myrtle Beach surpassed the threshold for potentially unsafe bacteria counts 82% of the time, according to John Rumpler, the nonprofit’s clean water director and senior attorney.

“We think that’s a reasonable threshold,” Rumpler said. “The public deserves to know if there’s a threat to their health.”

DHEC said the EPA’s threshold for enterococcus bacteria of 110cfu per 100 milliliter has been in place since 2012, and the Beach Action Value “is not a recommended standard for the protection of human health in recreational saltwater bodies.”

Other beaches had far lower potentially unsafe swimming days according to the study’s standard. Out of 78 days tested at North Myrtle Beach, 23 of the days had too-high pollution levels. Thirty-one of 73 test days were deemed potentially unsafe at the Town of Briarcliffe Acres. While tested on only 10 days, two of those days on Harbor and Hunting islands in Beaufort County had unacceptable pollution levels. Seabrook Island in Charleston County also had two potentially unsafe days out of 10 test days.

Local officials also say the water quality at Myrtle Beach gets a bad rap because of the number of sites that are tested.

Typically, water quality testing is done on what Rumpler called a “distinct” beach. On test days, a sample is taken from just one site on those beaches, and the test results are sent to the EPA. If the beach is tested 30 days out of the year, it would have 30 samples. And that beach could be as small as a half-mile.

At Myrtle Beach, the state checks 13 test sites along the city’s 10 miles of beaches.

“A single location could be sampled for each beach; However, DHEC wants to provide the best data possible for residents and tourists as part of our mission to protect public health,” Renwick said.

However, the number of samples make the data hard to untangle, Rumpler said. If a single test site sample has fecal indicator bacteria levels above the threshold Rumpler uses, the nonprofit declares the entire 10-mile beach as having a “potentially unsafe day.”

Mark Kruea, the city spokesperson, argued that if a high sample is taken from a 200-foot section of beach, that accounts for a tiny portion of Myrtle Beach’s shoreline while the rest of the beach could be within safe levels.

“Yet the whole beach is credited with a ‘bad day’?” Kruea said. “Such assumptions leave a lot to be desired.”

Myrtle Beach by the numbers

Since the 1990s, DHEC has tested Myrtle Beach’s water quality out of “an abundance of caution,” the city says, because of the millions of swimmers and visitors who use it.

The department has closely followed the EPA’s method for measuring fecal indicator bacteria levels that could cause illness in swimmers. The EPA’s threshold is recognized as the recommended standard for putting out swimming advisories.

But even when applying the lower threshold, Myrtle Beach’s ocean waters can be a concern.

Each year from May 1 to Oct. 1, DHEC sends out short- or long-term advisories when there’s an increased possibility of high bacteria levels, typically where stormwater from pipes or small creeks flow across the beach and into the ocean, Renwick said.

Short-term advisories last a day or two and are triggered when sample tests are above threshold levels on two consecutive days. The advisories can also be issued when the first sample exceeds the appropriate level and the test site is near a potential source of bacteria, such as a stormwater drain, according to DHEC.

Between May 1 to Oct. 1 last year, five short-term station advisories were issued at Myrtle Beach, according to DHEC.

Long-term advisories are issued for monitoring locations where more than 10% of the enterococcus data collected over the past five years exceeds the EPA’s standard for the bacteria, according to DHEC. The need for a long-term advisories are reassessed each year. Those advisories are often located where stormwater from pipes or small creeks flows across the beach and into the ocean, Renwick said.

Long-term advisories are removed when fecal indicator bacteria levels show improvement and less than 10% of the samples exceed the standard.

In 2022, over a quarter of the state’s short-term advisories were issued for Myrtle Beach locations, according to Renwick. Myrtle Beach also made up 53% of South Carolina’s 17 long-term alerts. This year, 11 test sites along Myrtle Beach are under long-term advisories.

That doesn’t mean the beach is closing or the warning bars swimming, Kruea said, adding that it means a swim advisory is triggered.

“When we do have a (short-term) swimming advisory, it typically is for a day ... and for an area of a few hundred feet,” he said.

Myrtle Beach does not have ports, factory farming, or heavy industry, and its sanitary sewer system and stormwater are separate, all of which can impact water quality. Renwick said most of the time, the fecal matter comes from pet and bird waste in the stormwater system. There is the potential that the city’s aging sewer system could leak into stormwater systems, but they are closely monitored, she added.

However, Myrtle Beach’s shoreline is heavily developed.

Drainage pipes to deep-water outfalls

For decades city officials have been working to shore up Myrtle Beach’s water quality.

More recently, that has included installing deep-water outfalls to help move stormwater around and prevent it from affecting ocean water quality in swimming areas. Different from the beach’s drainage pipes and swashes, deep-water outfalls work to transport rainwater beneath the ocean, over 1,000 feet and past the surf zone.

Some drainage pipes remain on the beach. In the fall, construction will begin on the fifth deep-water outfall, at 24th Avenue North, Kruea said. When that’s complete, 11 of the on-beach pipes will be removed. Currently the beach has between two and three dozen on-beach pipes, with some being as small as 8 inches in diameter while others are up to 36 inches, Kruea said.

The city received a $30 million state grant and $15 million in federal dollars is pending for the newest outfall project.

In the past 25 years, Myrtle Beach has spent about $80 million to improve and manage its stormwater. Kruea said the money spent doesn’t indicate significant problems on a routine basis. Rather the city’s investments and efforts have produced “very good ocean water quality.”

Editor’s note: A previous version of this article showed a photo of North Myrtle Beach, not Myrtle Beach. It has since been corrected.