RALEIGH, N.C./NEW YORK (Reuters) - Tropical Storm Florence could taint North Carolina waterways with murky coal ash and toxic hog waste as heavy rains test environmental rules written with milder weather in mind, carrying the risk of contaminating water with bacteria like salmonella, officials said on Friday.

A downed tree blocks a local street during the passing of Hurricane Florence the town of New Bern, North Carolina, U.S., September 14, 2018. REUTERS/Eduardo Munoz

Many of the state’s environmental codes were written to withstand a 25- or 100-year storm. But Florence promises heavy rains that some regions might not see in a thousand years, straining systems meant to keep state residents safe.

The deluge could push industrial waste sites to the limit, Governor Roy Cooper said on Friday.

“All of the infrastructure here is going to be tested,” Cooper told a news conference. “We are deeply concerned about the inland flooding.”

Florence would not be the first test of North Carolina manure pits, or “lagoons.”

Sixteen lagoons flooded under the foot of rain that came with Hurricane Matthew in 2016. The southeast part of the state is expected to get more than twice that amount in the days ahead, said Bryce Link, a meteorologist at DTN Marine Weather, a forecasting service.

There are 62 industrial hog farms within North Carolina’s 100-year floodplain, environmentalists estimate, and Duke Energy Corp has four coal ash sites in the coastal area touched by Florence. If excrement escapes from the lagoons where it is stored, it could potentially contaminate drinking water with bacteria like salmonella, which can cause digestive problems, and, in certain vulnerable patients cause E. coli.

The U.S. Environmental Protection Agency is working with storm-struck states and is ready to respond to any breaches, a spokeswoman, Maggie Sauerhage, said.

Animal feeding operations above a certain size need to be “designed and operated to handle the rainfall and runoff from 25-year 24-hour storms,” Sauerhage said in an emailed response to questions from Reuters. Even in the midst of a storm, these feeding sites must report leaks, she said.

In North Carolina, hog and poultry waste pits make up 6,848 acres of land according to a report from the Environmental Working Group.

Still, North Carolina has fewer flood-prone hog farms than it did when Hurricane Floyd inundated about 50 sites in 1999 and sparked statewide reforms.

Ash pits and other embankments have ruptured under heavy rain in the past, and Duke Energy has agreed to secure the sites in North Carolina’s lowland areas - but that work is ongoing.

Erin Culbert, a spokeswoman for Duke Energy, said the utility was ready to respond as needed to the storm.

There is, however, disagreement over the risk posed by Florence.

Andy Curliss, head of the North Carolina Pork Council, said spill dangers are overblown, noting that hog farmers have faced severe weather before.

“This is not the first hurricane to hit North Carolina,” said Curliss, who noted that many lagoons are at a low point across the state at this time of year.

But a state lawmaker said that hurricanes have led to dangerous spills in recent years and North Carolina’s laws are too lax to confront severe storms such as Florence.

“As a state, we have put our head in the sand,” Representative Pricey Harrison said. “Past storms should have been a wakeup call.”