Yes, there absolutely are fuel additives that are completely safe for use in diesels. Berryman offers a family of such high-performance products including Diesel Injector Cleaner (part #0518), Diesel Cetane Booster (part #0517), and All-Season Diesel Fuel Treatment (part #0512). Just look for the bright green Berryman labels that tout our new “IDI Deposit Buster” capability to know you’re getting the most effective diesel fuel additive chemistry available.