Toxic Carcinogens and LED Retrofits from HPS

By Brian Gandy Founder, Sustainable Terrains / Relamp & Relax Program

I’ve been deep in the weeds on researching and recycling HPS for the last year and have a current project that has brough up a hidden poison. This project is in traditional horticulture and the HPS fixtures are dinosaurs. I've don't plenty of retrofits in the past. Nothing unusual about that. But what I uncovered along the way is something that too many rebate programs and LED upgrade consultants are still ignoring: what happens to the fixtures you take down?

I’m not just talking about lamp recycling, which, to be clear, is required by law in California due to mercury content and should be standard practice everywhere. I’m talking about the ballast, specifically the hidden risk buried inside older systems built before digital ballasts were the norm.

Take this example: A batch of 600W PL Light Systems HPS fixtures from July 1998. Solid product. Durable. But inside those magnetic ballasts is a component that’s often overlooked, the capacitor. These aren’t just power storage devices. In many older models, they were built with PCBs (polychlorinated biphenyls)—a now-banned toxic compound and global carcinogen.

If you’re in this industry, you’ve probably heard of PCBs. If you’ve handled these older ballasts, there’s a good chance you’ve unknowingly handled them too.

Here’s the bottom line:

• Standard e-waste might cost $0.30 to $0.50 per pound to dispose of.

• Ballasts containing PCBs? That cost jumps to $6 to $8 per pound.

• These older fixtures can weigh 25 to 30 pounds each, making the real cost $80+ per fixture just to recycle them safely.

And that doesn’t even include the lamps themselves. Single-ended HPS lamps (common with these old systems) are 3x heavier than modern double-ended bulbs and run $10+ per lamp to recycle properly.

So, while rebate providers are happy to tout the energy savings of LED retrofits, the actual environmental footprint of these upgrades tells a more complicated story. If we’re pulling down toxic hardware and dumping it in a landfill under the guise of sustainability, we’re not solving a problem—we’re just shifting the burden downstream.

This isn’t about nostalgia for old gear. It’s about accountability. You can't claim you're improving efficiency while ignoring the hazardous waste left behind. (Speaking of old gear, my facilitator here said he was born around the time these fixtures were hung, and I had my learner's permit.)

And yet, most rebate programs don’t account for this at all. The logistics, labor, insurance, packaging, compliance paperwork, and specialized handling needed to safely remove and recycle these materials? Not covered. Not mentioned. Not priced in.

I’ve been in this game long enough to know how the sausage gets made. Rebate facilitators often act as middlemen, eager to clip a profit from the rebate spread without truly engaging with the operational or environmental side of the retrofit. That’s a problem.

What needs to happen—and what I’m pushing for now, is for utilities and power companies themselves to take this seriously. If you’re writing the check for a retrofit, you should be writing one for recycling, too.

Because yes, the watt-for-watt savings look good on paper. But the real picture: the environmental impact, the toxic load, the compliance risk, that’s what tells the truth.

And if we don’t build that into our sustainability math, then we’re not being honest about what the transition true costs.

Every lamp recycled helps grow tomorrow’s cultivation systems. Let’s make sure we’re not trading one invisible cost for another.

Author Note: Brian Gandy leads the Relamp & Relax program at Sustainable Terrains, helping cultivators transition from legacy lighting to cleaner, safer systems—without leaving a trail of toxic waste in the process.

If you’re working on a lighting upgrade or writing rebates for these conversions, reach out. If you don’t work with us, work with someone, but do the right thing and get lamps and e-waste to an appropriate recycling channel.