A high-profile series of dog deaths has awakened the public to the growing problem of toxic algal blooms, spurred by rising temperatures and pollution.

The blooms are emerging as a national, not just regional, concern, according to preliminary data reported to the U.S. Environmental Protection Agency through July. Samples taken from New Jersey to California, and from Texas to Washington state, all show evidence of toxins given off by the blooms.

Since 2018, when the EPA started collecting the latest batch of data, algal blooms have been documented near the intakes of water treatment plants at least 130 times.