A former school groundskeeper, diagnosed with terminal cancer, told a San Francisco jury Monday that he called a Monsanto Co. hotline twice - once before his diagnosis, once after - and asked whether the herbicide he was spraying on the job, the most widely used weed killer in the world, could cause harm to humans. Both times ... the person at the other end of the line listened to his account of being accidentally doused with the herbicide glyphosate, and said someone would call him back. No one ever did. I would never have sprayed the product around school grounds or around people if I thought it would cause them harm," Johnson told a Superior Court jury. Johnson ... was diagnosed with non-Hodgkin lymphoma in October 2014 and with ... a more aggressive form of the cancer in March 2015. Even after the latter diagnosis, Johnson said he continued to spray Monsanto's product, a high-concentration brand of glyphosate called Ranger Pro, until he became convinced that it was dangerous and refused to use it in his final months on the job. His damage suit, now into its third week, is the first of about 4,000 nationwide to go to trial against Monsanto, now a subsidiary of Bayer. In 2015, the World Health Organization's International Agency for Research on Cancer classified glyphosate as a probable human carcinogen. [Johnson] said ... a supervisor told him the product was safe as long as he wore long-sleeved shirts, pants, shoes and socks.