Recent samples collected by researchers from Kelp Watch and Cal State Long Beach professors have determined that no detectable radiation has entered the ecosystem along the West Coast since the disaster, which occurred in 2011.

Scientists collected samples from sites ranging from Baja Mexico to Alaska, including locations in Long Beach, according to a release.

“Results from our fifth sampling period from March through June of this year were very similar to the previous sampling periods obtained over the past two years and demonstrate no detectable amounts of Cesium 134 or elevated Cesium 137 levels in kelp that could be attributed to the Fukushima disaster,” said CSULB’s Dr. Steven Manley, a professor in Department of Biological Sciences.

Manley and Dr. Kai Vetter from UC Berkely started Kelp Watch in 2014 as a direct response to the disaster, with the aim of using kelp beds to detect radioactive seawater coming from Fukushima.

The kelp beds reportedly make it easy to detect Cesium 134, a radioactive isotope that was released into the atmosphere as a result of the disaster. Any detection of the isotope would mean the radiation from the incident traveled to California.

Small traces of radiation were found in the Port of Long Beach—Iodine-131—which is due to local sources of persistent waste and waste treatment, according to the release.