The radioactive plume of contaminated water said to be heading across the Pacific Ocean after Japan’s 2011 Fukushima nuclear disaster will reach the United States within a month, scientists now think.

Tuesday marks the third anniversary of the earthquake, tsunami and nuclear disaster, known in Japan as 3.11. The disaster killed nearly 16,000 people and left more than 2,000 unaccounted for in vast areas of its northern coast. Since then, the country has struggled to rebuild tsunami-hit communities and to clean up radiation from the nuclear crisis. About 50,000 people from Fukushima are still unable to return home due to concerns over radiation.

Police officers come the area for any signs of missing people three years after the disaster in Namie, near the striken TEPCO Fukushima Dai-ichi nuclear plant in Fukushima prefecture on March 10, 2014, one day before the third anniversary of March 11 massive earthquake and tsunami. The 9.0 magnitude earthquake in 2011 sent a huge wall of water into the coast of the Tohoku region, splintering whole communities, ruining swathes of prime farmland and killing nearly 19,000 people. (AFP/YOSHIKAZU TSUNO)

Officials comb the area for any signs of missing people three years after the disaster in Namie, near the striken TEPCO Fukushima Dai-ichi nuclear plant in Fukushima prefecture on March 10, 2014, one day before the third anniversary of the March 11, 2011 massive earthquake and tsunami. The 9.0 magnitude earthquake sent a huge wall of water into the coast of the Tohoku region, splintering whole communities, ruining swathes of prime farmland and killing nearly 16,000 people. (AFP/Yoshikazu Tsuno)

Here’s what you need to know about how this traveling plume could impact human and marine health in North America.

Where and when?

According to scientific models analyzed by a team at Woods Hole Oceanographic Institute, the plume in the Pacific Ocean will reach Alaska and coastal Canada first, and then will hit Hawaii and the rest of North America.

It is expected to hit the U.S. in April. You can keep up to do with current radiation levels on the Center for Marine and Environmental Radiation’s website.

How will it impact human health?

The levels of expected radiation are likely to be so small that it won’t negatively impact human health, according to the California Department of Public Health.

“We are not predicting that the levels will be a direct human health concern, but we can’t confirm that without samples,” Ken Buesseler, a Woods Hole senior scientist and director of the Center for Marine and Environmental Radioactivity, told the Huffington Post.

What about marine life?

As of right now, Woods Hole reports that most marine life contaminated with Fukushima radiation are mostly concentrated near the reactor site. The research institute noted that even though animals that leave the site might have some isotopes, some flush out of their systems naturally.

A staff member of the Tokyo Electric Power Co. (TEPCO) measures radiation levels inside the central control room of the No. 1 and No. 2 reactors at the Fukushima Dai-ichi nuclear power plant in Okuma town, Fukushima prefecture, northeastern Japan, Monday, March 10, 2014. The radioactive water that has accumulated at the crippled nuclear power plant remains the biggest problem hampering the cleanup process three years after the disaster. (AP/Koji Sasahara, Pool)

A staff member of the Tokyo Electric Power Co. (TEPCO) measures radiation levels inside the central control room of the No. 1 and No. 2 reactors at the Fukushima Dai-ichi nuclear power plant in Okuma town, Fukushima prefecture, northeastern Japan, Monday, March 10, 2014. The radioactive water that has accumulated at the crippled nuclear power plant remains the biggest problem hampering the cleanup process three years after the disaster. (AP/Koji Sasahara, Pool)

Need for more monitoring?

“Whether you agree with predictions that levels of radiation along the Pacific Coast of North America will be too low to be of human health concern or to impact fisheries and marine life, we can all agree that radiation should be monitored, and we are asking for your help to make that happen,” Buesseler said.

Buesseler launched a campaign in January, which has since raised about $24,000 in individual donations, to collect more water samples along the West Coast, something he thinks the federal government should be doing but says it isn’t.

Buesseler said he thinks more data will help keep the public informed of what’s actually going on.

“The unknown can breed fear. But in this case, science can give us the information we all need in order to make informed decisions,” he said.

According to USA Today, marine biologist Steven Manley from California State University-Long Beach is monitoring kelp to study the potential impact of any radiation contamination.

Roger Gilbert, a radiation oncologist, said he became involved with Buesseler’s project in order to dispel any “fear-mongering on the Internet about allegedly high levels of Fukushima radiation in the coastal waters of California.”

‘Fear-mongering,’ you say?

California officials in January were forced to address concerns that beaches were contaminated after viral videos like the one below showed radiation monitors picking up elevated levels:

The measurements in this video were said to be accurate but actually of naturally occurring radiation, not from Fukushima.

“There is no public health risk at California beaches due to radioactivity related to events at Fukushima,” the department’s spokeswoman Wendy Hopkins said, according to International Business Times.

Watch this video from Woods Hole for more in the impact of Fukushima radiation the ocean:

The Associated Press contributed to this report. Featured image via Shutterstock.