Pennsylvania American Water said algae growth in Lake Oneida is impacting the taste and odor of water in Butler and several other municipalities, but the water remains safe to drink.

The company said it is addressing taste and odor issues caused by naturally occurring algae in the lake, which is a reservoir for Butler, East Butler and Saxonburg, and parts of Butler, Center, Oakland and Summit townships.

The algae growth is due to hot weather and elevated levels of nutrients, the company said. The algae — a microscopic plant — produces an odd, but harmless taste or odor. The drinking water continues to meet Pennsylvania Department of Environmental Protection and U.S. Environmental Protection Agency standards. There is no threat to public health, the company said.

The company said it recently changed its treatment process by increasing the use of carbon to address these issues. Carbon is used during the regular treatment process to adsorb odors from the water.