San Diego substance abuse experts say a disturbing trend in the drug trade may soon claim many lives in the county.While experts said local teens used to be scared of heroin, that fear has faded while the potency of the drug has jumped."I tried it because it was around," said John.At age 19, John became addicted to heroin. Soon after, he began dealing the drug."It's definitely getting stronger," he told 10News.The heroin he sold was a very high 50 percent pure. He said he recently saw one user overdose."[He] thought he could handle it. He tried it, and next thing you know he's on the ground, flopping like a fish," said John.The user survived the incident, and so did Will Jones."[I] missed a vein and shot the dope in there," Jones said.The scars are many for Jones, an addict-turned-treatment program manager at the McAlister Institute, a local center that helps those whose lives have been affected by drug use.Jones said black tar heroin from Mexico is more potent than ever and is as much as 80 to 90 percent pure."Before you even get the needle out of your arms, person overdoses and ends up dead," said Jones.Nationwide, heroin deaths are at record numbers.In San Diego County, there were 52 deaths from heroin overdoses in 2009 -- up 27 percent in two years.Experts said improvement in production methods have ramped up potency and lowered prices."It's a deadly combination. It's a death wish," said Jones.It is a combination that is attracting teens, according to Jones.In his program, Jones estimated the number of teen clients addicted to heroin has increased by 50 percent in the last 5 years.After heroin destroyed much of his life, John got help.However, many fear with heroin more deadly than ever, others will never get the chance to get help."A lot of families are going to grieve," said Jones.Law enforcement is aware of the growing issue, but experts said the tide will be tough to stop.Heroin seizures jumped 200 percent at the U.S.-Mexico border in 2009, and the pace is similar in 2010.